Update template docs: remove dated Jest info, improve consistency between all 3, add GitHub Actions docs

[agilgur5]

These haven't gotten any attention in a while and I forgot they existed for a bit (I don't use create myself). Bring them up to speed:

• (docs): update outdated Jest info in template READMEs
  • follow-up to #536
• (docs): remove version/permalink refs in template READMEs
  • relates to #679 , #545
• (docs): improve consistency in template READMEs
  • follow-up to #360
• (docs): remove duplicative "Using the Playground" section
• (docs): add GitHub Actions info to template CI READMEs
  • follow-up to #457
• (docs): basic template README should be like React ones