chore: v14 RC preparations

[mdjastrzebski]

Summary

• create Changelog from v14
• update migration guide
• adjust codemods to use test-renderer 1.x and RNTL ^14.0.0-0

Test plan

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.37%. Comparing base (8ed8efc) to head (5d69191).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1906   +/-   ##
=======================================
  Coverage   98.37%   98.37%           
=======================================
  Files          79       79           
  Lines        1480     1480           
  Branches      393      393           
=======================================
  Hits         1456     1456           
  Misses         24       24           

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