refactor: rename objects representing workspace

See merge request gitlab-org/gitlab-vscode-extension!198

chore(npm): run npm upgrade to update all dependencies

See merge request gitlab-org/gitlab-vscode-extension!182

This prevents confusion between GitLab project and VS Code workspace.
The current legacy naming that uses the name "project" to represent
VS Code workspace is diverging from an established naming and
confuses contributors.

The work "project" is used throughout the codebase for GitLab project
and it was causing confusion when two variables named 'project' meant
different things.

fix: workspace in project subfolder breaks Open active file on GitLab

See merge request gitlab-org/gitlab-vscode-extension!185

This command prefixes the path opened by the “Copy link to active file
on GitLab” and “Open active file on GitLab” commands.

This is useful to fix the link generated by the above file link commands
if your VS Code workspace root isn’t the git root.

Convert typescript integration tests to unit tests

See merge request gitlab-org/gitlab-vscode-extension!192

feat(mr review): deleting comments on MR diff

See merge request gitlab-org/gitlab-vscode-extension!195

feat(mr review): resolving and unresolving discussions

See merge request gitlab-org/gitlab-vscode-extension!194

feat(mr review): display whether discussion is resolved or not

See merge request gitlab-org/gitlab-vscode-extension!193

refactor: introduce separate classes for threads and comments

See merge request gitlab-org/gitlab-vscode-extension!190

All logic related to creating vscode.CommentThread and
setting the correct properties has been extracted to one class.

This class will be responsible for resolving threads in the future.

The GitLabComment is going to be responsible for all comment-related
functionality like editing, deleting and reacting.

The testing responsibility is now strictly divided. The tree_view test
is responsible for validating querying lists of issues/MRs and
showing these lists as items in the tree_view.

The new mr_review test is responsible for all interactions with the MR
item, including showing changed files when clicked, fetching
discussions and any future review functionality.

This commit splits the "shows project merge requests assigned to me with
changed files" test in two and all other tests just moved around
unchanged.

chore(ci variables): update the ci_variables.json

See merge request gitlab-org/gitlab-vscode-extension!191

refactor: use union types to better represent discussions

See merge request gitlab-org/gitlab-vscode-extension!189

Developer documentation review and update.

See merge request gitlab-org/gitlab-vscode-extension!188

The testing strategy has been written before we started
writing tests. Now after months of writign tests, lot of the
processes changed.

We migrated to TS and introduced new concepts since the last update.

This is a snippet from a book Effective TypeScript:

WARNING
The examples in this item prefix type names with I or T solely to
indicate how they were defined. You should not do this in your code!
Prefixing interface types with I is common in C#, and this convention
made some inroads in the early days of TypeScript. But it is considered
bad style today because it’s unnecessary, adds little value, and is not
consistently followed in the standard libraries.