Add api end point to print the current database state in VTOrc

[GuptaManan100]

Description

This PR adds a new API endpoint for VTOrc, that allows the users to see the current database state of the instance. This is useful for debugging.

The new endpoint is /api/database-state and it looks like -

Related Issue(s)

• Fixes Feature Request: VTOrc database state as an API #15484

Checklist

• "Backport to:" labels have been added if this change should be back-ported to release branches
• If this change is to be back-ported to previous releases, a justification is included in the PR description
• Tests were added or are not required
• Did the new or modified tests pass consistently locally and on CI?
• Documentation was added or is not required - Add docs for the new /api/database-state api endpoint website#1705

Deployment Notes

[vitess-bot]

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[codecov]

Codecov Report

Attention: Patch coverage is 64.28571% with 10 lines in your changes are missing coverage. Please review.

Project coverage is 65.73%. Comparing base (d1d1901) to head (1716eec).
Report is 25 commits behind head on main.

Files	Patch %	Lines
go/vt/vtorc/server/api.go	11.11%	8 Missing ⚠️
go/vt/vtorc/inst/instance_dao.go	89.47%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #15485      +/-   ##
==========================================
+ Coverage   65.65%   65.73%   +0.08%     
==========================================
  Files        1563     1560       -3     
  Lines      194414   194572     +158     
==========================================
+ Hits       127640   127902     +262     
+ Misses      66774    66670     -104     

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[deepthi]

LGTM. Just one question about possibly unused tables.