This exposes `Note`s on Issues & MergeRequests using a
`Types::Notes::NoteableType` in GraphQL.

Exposing notes on a new type can be done by implementing the
`NoteableType` interface on the type. The presented object should
be a `Noteable`.

Since we're not actually  loading commits in that loader, but we're
loading blobs with LFS oids in batch and returning only the oids.

This helps reduce complexity for non-connections

Since the `GraphQL::ID_TYPE` usages should represent globally unique
ids, this changes some fields for which this is not the case into
strings.

The `ID_TYPE` is a specialised, so this change should be backwards
compatible.

https://graphql-ruby.org/type_definitions/scalars.html

This exposes all fields named `id` as GlobalIDs so they can be used
across our entire GraphQL implementation.

When the objects loaded are `ApplicationRecord`s. We'll use our
existing batchloading to find them. Otherwise, we'll fall back to the
default implementation of `GlobalID`: Calling the `.find` method on
the class.

We can query namespaces, and nested projects.

Projects now exposes statistics

and allow passing of child_complexity to the
'resolver_complexity' metho

If a field is a resolver, its complexity is automatically
increased. By default we add extra points for sort and search
arguments (which will be common for various resolvers).

For specific resolvers we add field-specific complexity, e.g.
for Issues complexity is increased if we filter issues by `labelName`
(because then SQL query is more complex). We may want to tune these
values in future depending on real-life results.

Complexity is also dependent on the number of loaded nodes, but only
if we don't search by specific ID(s). Also added complexity is limited
(by default only twice more than child complexity) - the reason is
that although it's more complex to process more items, the complexity
increase is not linear (there is not so much difference between loading
10, 20 or 100 records from DB).

and removing unnecessary code

Add new query for Groups, with new
GroupType and NamespaceType

It makes all Types::BaseField default to a complexity of 1.

Queries themselves now have limited complexity, scaled
to the type of user: no user, authenticated user, or an
admin user.

Enables authorizations to be defined on GraphQL Types.

    module Types
      class ProjectType < BaseObject
        authorize :read_project
      end
    end

If a field has authorizations defined on it, and the return type of the
field also has authorizations defined on it. then all of the combined
permissions in the authorizations will be checked and must pass.

Connection fields are checked by "digging" to find the type class of the
"node" field in the expected location of edges->node.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/54417

- Show pipeline status, title, MR Status and project path
- Popover attached to gitlab flavored markdown everywhere, including:
  + MR/Issue Title
  + MR/Issue description
  + MR/Issue comments
  + Rendered markdown files

Previously GraphQL field authorization happened like this:

    class ProjectType
      field :my_field, MyFieldType do
        authorize :permission
      end
    end

This change allowed us to authorize like this instead:

    class ProjectType
      field :my_field, MyFieldType, authorize: :permission
    end

A new initializer registers the `authorize` metadata keyword on GraphQL
Schema Objects and Fields, and we can collect this data within the
context of Instrumentation like this:

    field.metadata[:authorize]

The previous functionality of authorize is still being used for
mutations, as the #authorize method here is called at during the code
that executes during the mutation, rather than when a field resolves.

https://gitlab.com/gitlab-org/gitlab-ce/issues/57828

Signed-off-by: NRémy Coutable <remy@rymai.me>

defaultBranch and ciConfigPath should only be available to users with
the :download_code permission for the Project, as the respository might
be private.

When implementing the authorize check on these properties, it was
found that our current Graphql::Authorize::Instrumentation class does
not work with fields that resolve to subclasses of
GraphQL::Schema::Scalar, like GraphQL::STRING_TYPE.

After discussion with other Create Team members, it has been decided
that because the GraphQL API is not GA, to remove these properties from
ProjectType, and instead implement them as part of epic
https://gitlab.com/groups/gitlab-org/-/epics/711

Issue:
https://gitlab.com/gitlab-org/gitlab-ce/issues/55316

And add tests

And fix the tests so that it won't run into circular paths.

Signed-off-by: NRémy Coutable <remy@rymai.me>

This suggests possibly related issues when the user types a title.

This uses GraphQL to allow the frontend to request the exact
data that is requires. We also get free caching through the Vue Apollo
plugin.

With this we can include the ability to import .graphql files in JS
and Vue files.
Also we now have the Vue test utils library to make testing
Vue components easier.

Closes #22071

Partially addresses #47424.

This is mainly the setup of mutations for GraphQL. Including
authorization and basic return type-structure.

This adds Keyset pagination to GraphQL lists. PoC for that is
pipelines on merge requests and projects.

When paginating a list, the base-64 encoded id of the ordering
field (in most cases the primary key) can be passed in the `before` or
`after` GraphQL argument.

This adds a reusable way to expose permissions for a user to types in
GraphQL.

This allows the user to get a single MR nested in a GraphQL project
query.

Since we need the full path and the iid anyway, this makes more sense
than having a root query that needs the full path as well.

- All definitions have been replaced by classes:
  http://graphql-ruby.org/schema/class_based_api.html
- Authorization & Presentation have been refactored to work in the
  class based system
- Loaders have been replaced by resolvers
- Times are now coersed as ISO 8601

By specifying a presenter for the object type, we can keep the logic
out of `GitlabSchema`.

The presenter gets initialized using the object being presented, and
the context (including the `current_user`).