Updating default value for kube-api-qps and kube-api-burst for kapp

[prembhaskal]

What this PR does / why we need it:

This PR is changing the default values for kube-api-qps and kube-api-burst limits.
It is reducing it from 1000 (for both) to 50 for kube-api-qps and 100 for kube-api-burst.

Reasoning behind changes:

• Kapp is used in kapp-controller for App reconciliation. kapp-controller has by default App CR concurrency of 10. so currently total api-qps = 1000*10 = 10k and burst-qps = 10k. This high qps can overload apiserver and cause slowness in cluster.
• With lower default values of 50 for qps and 100 for burst, we limit the total api-qps to 500 and 1000 when AppCR concurrency = 10.
• Also for any small to medium App (having less than 50 resources), the api-qps of 50 and burst of 100 are sufficient and don't cause slowness in reconcile time.
  TODO - add results here from excel.
• Any large App (having more than 50 resources), the default values can be changed using the command line options.

Which issue(s) this PR fixes:

Fixes #

Does this PR introduce a user-facing change?

None

Additional Notes for your reviewer:

Review Checklist:

• Follows the developer guidelines
• Relevant tests are added or updated
• Relevant docs in this repo added or updated
• Relevant carvel.dev docs added or updated in a separate PR and there's
  a link to that PR
• Code is at least as readable and maintainable as it was before this
  change

Additional documentation e.g., Proposal, usage docs, etc.:

[rohitagg2020]

LGTM

[prembhaskal]

making changes in kapp-controller, not directly in kapp, so closing this.