Add GitHub issue templates

[ryanopande]

I am duplicating issue templates from ml5-website-v02-docsify into this repo.

Templates to add:

• bug---maintenance-report.yml
• compatibility---accessibility-fixes.yml
• config.yml
• content-update.yml
  - renamed from documentation-update.yml, repurposed for website content instead of docs, updated dropdown options, added page link field
• feature_request.yml

[MOQN]

Thank you!!! @ryanopande