docs: update the available CRDs in getting started

[Rajakavitha1]

• updated the types of CRDs in apisix

Fixes: #1522

Type of change:

• Bugfix
• New feature provided
• Improve performance
• Backport patches
• Documentation
• Refactor
• Chore
• CI/CD or Tests

What this PR does / why we need it:

Pre-submission checklist:

• Did you explain what problem does this PR solve? Or what new features have been added?
• Have you added corresponding test cases?
• Have you modified the corresponding document?
• Is this PR backward compatible? If it is not backward compatible, please discuss on the mailing list first

[kayx23]

Please note that APISIX Consumer doc is added to concepts in this PR: #2074

Plugin config is also available under concepts. Why not link to there?

[github-actions]

This pull request has been marked as stale due to 60 days of inactivity. It will be closed in 30 days if no further activity occurs. If you think that's incorrect or this pull request should instead be reviewed, please simply write any comment. Even if closed, you can still revive the PR at any time or discuss it on the dev@apisix.apache.org list. Thank you for your contributions.

[github-actions]

This pull request/issue has been closed due to lack of activity. If you think that is incorrect, or the pull request requires review, you can revive the PR at any time.