Add GitLab CI Runner Status Page

[smarr]

Technically, this feature doesn't really fit into ReBenchDB and should be part of GitLab or so.
Though, it seems the best place for me to maintain it for the moment.

This added page shows the results of a GitLab GraphQL query to show all runners and pipelines and jobs associated with a GitLab group.
The result is shown with the most recent and active jobs first.

The assumption is that one wants to know what's currently running, who queued a job, and who to talk to when there might be issues.

This PR adds dependencies on:

• graphql-request
• graphql
• nock for testing

TODOs

• look through added colors and sync with the rest of the styling
• test the dark mode
• possibly extract the CSS to files as we normally do
• add the same support for dark/light mode switching we have elsewhere

[smarr]

Since this looks like very large PR, the main element is just about 870 lines of change

$ git diff --stat master HEAD -- src
 src/backend/gitlab/graphql-api.ts          | 103 ++++++++++++++++++++++++
 src/backend/gitlab/html/index.html         | 137 ++++++++++++++++++++++++++++++++
 src/backend/gitlab/html/relative-time.html |   1 +
 src/backend/gitlab/html/tags.html          |   7 ++
 src/backend/gitlab/request-cache.ts        |  66 ++++++++++++++++
 src/backend/gitlab/runner-status.ts        | 448 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 src/backend/util.ts                        |  46 +++++++++--
 src/index.ts                               |  27 ++++++-
 src/shared/data-format.ts                  |  32 ++++++++
 9 files changed, 858 insertions(+), 9 deletions(-)