Modify rfc for deprecating Kind and Platform Provider

[ffjlabo]

What this PR does:

Modified the way to deprecate Kind and Platform Provider in the RFC for plugin architecture.

Why we need it:

We don't use the Kind and Platform Provider because we migrate the DB data before updating pipedv1.
After updated, the pipedv1 refers labels["kind"] and daployTarget instead of Kind and Platform Provider.

Which issue(s) this PR fixes:

Part of #5252
Related to #5358

Does this PR introduce a user-facing change?:

• How are users affected by this change:
• Is this breaking change:
• How to migrate (if breaking change):

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 25.44%. Comparing base (ab687f3) to head (5262dc4).
Report is 4 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #5365   +/-   ##
=======================================
  Coverage   25.44%   25.44%           
=======================================
  Files         446      446           
  Lines       47844    47844           
=======================================
  Hits        12172    12172           
  Misses      34720    34720           
  Partials      952      952           

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[Warashi]

I got your point. LGTM.

[khanhtc1202]

👍 LGTM