fix: Clarify README-type files from the community PoV

[mjang]

Proposed changes

Update instructions from the contributor PoV.

• Update F5 instructions
• Include instructions for linking to a GH issue in the PR template

Closes #ISSUE

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the contributing guidelines

• I have signed the F5 Contributor License Agreement (CLA)

• If applicable, I have added tests that prove my fix is effective or that my feature works

• If applicable, I have checked that any relevant tests pass after adding my changes

• I have updated any relevant documentation (README.md and CHANGELOG.md)

• I have rebased my branch onto main

• I will ensure my PR is targeting the main branch and pulling from my branch from my own fork

• If the change involves:

  • Code
  • Anything that resembles Personally identifying information (PII)
    • Make sure to use placeholders such as <username> in place of PII
  • URLs (watch for typosquatting)
  • Significant new/revised content

  In these cases, the change will require at least two (2) approvals before merging