Extends existing graphql's tracer with opentracing measurements. Because
it also adds Tracing::Graphql class (for opentracing), it also renames
Graphql::Tracing class to Graphql::GenericTracing to minimize confusion
with similar class names.

Updates the EnvironmentController#metrics_dashboard endpoint
to support a "dashboard" param, which can be used to specify
the filepath of a dashboard configuration from a project
repository. Dashboard configurations are expected to be
stored in .gitlab/dashboards/.

Updates dashboard post-processing steps to exclude custom
metrics, which should only display on the system dashboard.

Gitaly's FetchIntoObjectPool RPC will idempotently fetch objects into an
object pool. If the pool doesn't exist, it will create an empty pool
before attempting the fetch. This change adds client code as well as
specs to cover this behavior.

Having this as an instance method makes it easier to override in the
prepended `EE` module.

If we try to override this method on the module itself, it would not
be overridden correctly, depending on the load order.

In Rails 5, including `ActionView::Context` can have a significant and
hidden performance penalty because this module also includes
`ActionView::CompiledTemplates`. This means that any module that
includes ActionView::Context becomes a descendant of
`CompiledTemplates`.

When a partial is rendered for the first time, it runs
`ActionView::CompiledTemplates#module_eval`, which will evaluate a
string that defines a new method for that partial. For example, the
source of partial might be this string:

```
def _app_views_project_show_html_haml___12345(local_assigns, output)
  "hello world"
end
```

When this string is evaluated, the Ruby interpreter will define the
method and clear the global method cache for all descendants of
`ActionView::CompiledTemplates`. Previous to this change, we
inadvertently made a number of modules fall into this category:

* GroupChildEntity
* NoteUserEntity
* Notify
* MergeRequestUserEntity
* AnalyticsCommitEntity
* CommitEntity
* UserEntity
* Kaminari::Helpers::Paginator
* CurrentUserEntity
* ActionView::Base
* ActionDispatch::DebugExceptions::DebugView
* MarkupHelper
* MergeRequestPresenter

After this change:

* Kaminari::Helpers::Paginator
* ActionView::Base
* ActionDispatch::DebugExceptions::DebugView

Each time a partial is rendered for the first time, all methods for
those modules will have to be redefined. This can exact a significant
performance penalty.

How bad is this penalty? Using the following benchmark script, we can
use DTrace to sample the Ruby interpreter:

```
Benchmark.bm do |x|
  x.report do
    1000.times do
      ActionView::CompiledTemplates.module_eval("def testme\nend")
    end
  end
end
```

This revealed a 11x jump in the time spent in `core#define_method`
alone.

Rails 6 fixes this behavior by moving the `include CompiledTemplates`
into ActionView::Base so that including `ActionView::Context` doesn't
quietly affect other modules in this way.

Closes https://gitlab.com/gitlab-org/gitlab-ee/issues/11198

Before this commit the wrong namespace could have been used in
Prometheus queries for group-level installations.

This ports the changes from
https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/10462/
to CE

`sidekiq-cluster` is moved from `bin/` to `ee/bin` in EE code. This
is a corresponding change in CE.

Ruby 5.1 now requires keyword arguments to pass along parameters and
headers for ActionDispatch::Integration::RequestHelpers.

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/61051

This enables sending a chat message to Slack or Mattermost
  upon a successful, failed, or canceled deployment

This new table will be used to store the external_dashboard_url which
allows users to add a link to their external dashboards (ex Grafana)
to the Metrics dashboard.

Improve indent for cache paths

Improve indent and remove empty lines

Updates the gitaly client to use path_bytes field instead of the
deprecated path field in list_last_commits_for_tree_response.
Also adds a test to guard against non-utf8 path data

Inside a wiki, when we show the sidebar or browse to the `pages`,
all page contents are retrieved from Gitaly and that is a waste
of resources, since no content from that pages are going to be
showed.

This MR introduces the method `ProjectWiki#list_pages`,
which uses new wiki_list_pages RPC call to retrieve
pages without content

Also in the `WikisController` we're using the method to show
pages in the sidebar and also on the `pages` page.

Blob.lazy adds a blob to a batch to load at a later point, using the
BatchLoader library. Whenever any lazy blob's attributes are accessed,
all lazy blobs requested to that point will be loaded.

BatchLoader, the library we use for this, should only request items in a
batch once. That is, if we have these batches:

1. a, b, c
2. d, e, f

Then a, b, and c should only be requested in the first batch. But if you
modify the list of items in the batch, then the second batch will
request a, b, c, d, e, f, which is almost certainly not what we want!

https://github.com/exAspArk/batch-loader/issues/44 is the upstream issue
for this, but we can also solve this in our application by not modifying
the arguments we're using inside a BatchLoader batch.

Change MetricsDashboard::Service to inherit from BaseService so that
it can reuse methods like initialize, success, error.

- Order groups by descending order of priority.
- Order panels by descending order of weight.
- Perform sorting after adding project/custom metrics.

- Add 3 functions called find_or_create_panel,
find_or_create_panel_group, and find_or_create_metric to avoid having
to use 'send'.
- Remove an unused variable.
- Freeze a constant array.

This adds support for != and !~ operators
giving more flexibility in comparing values

Model.new.attributes now also returns encrypted attributes.