refactor(general): perform index compaction during repo maintenance

[julio-lopez]

Perform index epoch compaction and cleanup during repository maintenance.

• [x] Cleanup watermark and epoch markers on full maintenance
• [x] Advance epoch on quick maintenance
• [x] Advance epoch on full maintenance
• [x] Compact a single epoch on quick maintenance
• [x] Compact a single epoch on full maintenance
• [x] Range compaction on full maintenance

In the future (separate PR) we may want to perform single-epoch compaction for all eligible epochs in a single execution of full maintenance. TBD.

Followup to #3603 and #3645

Ref:

• #3638
• #3639

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 52.38095% with 20 lines in your changes are missing coverage. Please review.

Project coverage is 77.09%. Comparing base (cb455c6) to head (f4b88af). Report is 73 commits behind head on master.

Files	Patch %	Lines
repo/maintenance/maintenance_run.go	52.38%	13 Missing and 7 partials :warning:

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3651      +/-   ##
==========================================
+ Coverage   75.86%   77.09%   +1.22%     
==========================================
  Files         470      476       +6     
  Lines       37301    28902    -8399     
==========================================
- Hits        28299    22281    -6018     
+ Misses       7071     4693    -2378     
+ Partials     1931     1928       -3     

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