Feature export Harbor statistics as Prometheus metric

[tpoxa]

This PR exposes the Harbor statistics as Prometheus metric.

The data exposed as metrics are 1:1 taken from thestatistics API, including the name.

New Metrics

• harbor_statistics_private_project_amount
• harbor_statistics_private_repo_amount
• harbor_statistics_public_project_amount
• harbor_statistics_public_repo_amount
• harbor_statistics_total_project_amount
• harbor_statistics_total_repo_amount
• harbor_statistics_total_storage_consumption

Please indicate you've done the following:

• [x] Well-Written Title and Summary of the PR
• [x] Label the PR as needed. release-note/enhancement
• [x] Accepted the DCO. Commits without the DCO will delay acceptance.
• [x] Made sure tests are passing and test coverage is added if needed.
• [x] Considered the docs impact and opened a new docs issue or PR with docs changes if needed in website repository.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 58.88889% with 37 lines in your changes are missing coverage. Please review.

Project coverage is 70.65%. Comparing base (a3e1b1e) to head (6bc12b5). Report is 27 commits behind head on main.

:exclamation: Current head 6bc12b5 differs from pull request most recent head 5c949c1. Consider uploading reports for the commit 5c949c1 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #18679      +/-   ##
==========================================
+ Coverage   67.45%   70.65%   +3.19%     
==========================================
  Files         996      748     -248     
  Lines      109773    95932   -13841     
  Branches     2720        0    -2720     
==========================================
- Hits        74044    67776    -6268     
+ Misses      31747    24484    -7263     
+ Partials     3982     3672     -310     

Flag	Coverage Δ
unittests	70.65% <58.88%> (+3.19%)	:arrow_up:

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
src/pkg/exporter/exporter.go	6.66% <0.00%> (-0.23%)	:arrow_down:
src/pkg/exporter/statistics_collector.go	60.91% <60.91%> (ø)

... and 272 files with indirect coverage changes

[github-actions[bot]]

This PR is being marked stale due to a period of inactivty. If this PR is still relevant, please comment or remove the stale label. Otherwise, this PR will close in 30 days.

[github-actions[bot]]

This PR was closed because it has been stalled for 30 days with no activity. If this PR is still relevant, please re-open a new PR against main.

[wy65701436]

@Vad1mo since we've reached the FC of v2.10 this week, I just put it into the v2.11 candidate.

[Vad1mo]

@wy65701436 any chance we can get this merged into 2.11?