[TT-1913] Add CODEOWNERS, set up GitHub templates, and update docs

[jlucktay]

Description

• configured CODEOWNERS file to fallback auto-assign PRs to the Architect team if no other assignee is set
• added templates for GitHub issues and PRs
• did a formatting pass on the README

Related Issue

TT-1913.

Motivation and Context

More automation means less toil for humans.

Test Coverage For This Change

N/A

Screenshots (if appropriate)

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• Make sure you are requesting to pull a topic/feature/bugfix branch (right side). If PRing from your fork, don't come from your master!
• Make sure you are making a pull request against our master branch (left side). Also, it would be best if you started your change off our latest master.
• My change requires a change to the documentation.
  • If you've changed APIs, describe what needs to be updated in the documentation.
• I have updated the documentation accordingly.
• Modules and vendor dependencies have been updated; run go mod tidy && go mod vendor in applicable directories.
• I have added tests to cover my changes.
• All new and existing tests passed.
• Check your code additions will not fail linting checks:
  • gofmt -s -w .
  • go vet ./...
  • golangci-lint run

[excieve]

Thanks!