[WIP] Initialize VSchemaAPI

[beingnoble03]

Description

Test coverage:

go test ./go/vt/vtctl/vschema --coverprofile=c.out   
ok  	vitess.io/vitess/go/vt/vtctl/vschema	0.500s	coverage: 92.7% of statements

Related Issue(s)

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

Deployment Notes

[vitess-bot]

Review Checklist

Hello reviewers! 👋 Please follow this checklist when reviewing this Pull Request.

General

• Ensure that the Pull Request has a descriptive title.
• Ensure there is a link to an issue (except for internal cleanup and flaky test fixes), new features should have an RFC that documents use cases and test cases.

Tests

• Bug fixes should have at least one unit or end-to-end test, enhancement and new features should have a sufficient number of tests.

Documentation

• Apply the release notes (needs details) label if users need to know about this change.
• New features should be documented.
• There should be some code comments as to why things are implemented the way they are.
• There should be a comment at the top of each new or modified test to explain what the test does.

New flags

• Is this flag really necessary?
• Flag names must be clear and intuitive, use dashes (-), and have a clear help text.

If a workflow is added or modified:

• Each item in Jobs should be named in order to mark it as required.
• If the workflow needs to be marked as required, the maintainer team must be notified.

Backward compatibility

• Protobuf changes should be wire-compatible.
• Changes to _vt tables and RPCs need to be backward compatible.
• RPC changes should be compatible with vitess-operator
• If a flag is removed, then it should also be removed from vitess-operator and arewefastyet, if used there.
• vtctl command output order should be stable and awk-able.

[codecov]

Codecov Report

❌ Patch coverage is 37.16108% with 788 lines in your changes missing coverage. Please review.
✅ Project coverage is 67.41%. Comparing base (8937eb3) to head (1aa722d).
⚠️ Report is 295 commits behind head on main.

Files with missing lines	Patch %	Lines
go/cmd/vtctldclient/command/vschema.go	25.92%	220 Missing ⚠️
go/vt/vtadmin/http/vschema.go	0.00%	162 Missing ⚠️
go/vt/vtctl/grpcvtctldserver/server.go	2.61%	149 Missing ⚠️
go/vt/vtadmin/api.go	6.66%	126 Missing ⚠️
go/vt/vtctl/grpcvtctldclient/client_gen.go	0.00%	60 Missing ⚠️
go/vt/vtctl/vschema/vschema_api.go	86.60%	47 Missing ⚠️
go/vt/vtctl/localvtctldclient/client_gen.go	0.00%	24 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #17996      +/-   ##
==========================================
- Coverage   67.59%   67.41%   -0.18%     
==========================================
  Files        1598     1605       +7     
  Lines      260306   262622    +2316     
==========================================
+ Hits       175941   177034    +1093     
- Misses      84365    85588    +1223     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.

[github-actions]

This PR is being marked as stale because it has been open for 30 days with no activity. To rectify, you may do any of the following:

• Push additional commits to the associated branch.
• Remove the stale label.
• Add a comment indicating why it is not stale.

If no action is taken within 7 days, this PR will be closed.

[github-actions]

This PR is being marked as stale because it has been open for 30 days with no activity. To rectify, you may do any of the following:

• Push additional commits to the associated branch.
• Remove the stale label.
• Add a comment indicating why it is not stale.

If no action is taken within 7 days, this PR will be closed.

[github-actions]

This PR is being marked as stale because it has been open for 30 days with no activity. To rectify, you may do any of the following:

• Push additional commits to the associated branch.
• Remove the stale label.
• Add a comment indicating why it is not stale.

If no action is taken within 7 days, this PR will be closed.

[github-actions]

This PR is being marked as stale because it has been open for 30 days with no activity. To rectify, you may do any of the following:

• Push additional commits to the associated branch.
• Remove the stale label.
• Add a comment indicating why it is not stale.

If no action is taken within 7 days, this PR will be closed.

[github-actions]

This PR is being marked as stale because it has been open for 30 days with no activity. To rectify, you may do any of the following:

• Push additional commits to the associated branch.
• Remove the stale label.
• Add a comment indicating why it is not stale.

If no action is taken within 7 days, this PR will be closed.

[github-actions]

This PR is being marked as stale because it has been open for 30 days with no activity. To rectify, you may do any of the following:

• Push additional commits to the associated branch.
• Remove the stale label.
• Add a comment indicating why it is not stale.

If no action is taken within 7 days, this PR will be closed.