Docs - Update GH template links in docs

[theangchen]

Once the issues and pull request templates are created in GH

• We should update links in the docs to point to them rather than the issues page for the repo. Example here line 27.
• There may be other places we should add, like the Contribute page

Add this link to Contribution Guidelines:
https://github.com/NMFS-RADFish/boilerplate/issues/new/choose