Replaces many enums with union types

Adds state prop to issues & prs
Removes some enums in favor of union types

Removes `getPullRequestForBranch` from GitProviderService as it doesn't belong there

- To be used in the future

- Avoids blocking UI & improves perf of enrichment of autolinks & PRs
 - Affects inline blame, hovers, statusbar blame, autolinks
Improves performance of autolink detection
Improves line tracking & state management
 - Avoids using a class for state
 - Only resets when needed
 - Adds more state storage & updates state rather than replacing it
Adds a new CacheProvider for better caching

- Aligns with RichRemoteProvider call

Co-authored-by: Eric Amodio <eamodio@users.noreply.github.com>

Fixes leak with rich remote providers
Avoids needing repo remote subscriptions

Converts file changed web components to Lit

- Replaces "Toggle <x>: <state>" pattern with actual toggle action

- Bumps Graph component w/ new mulitline commit message rendering

- Removes pinning notion from search & compare view
 - Removes "Keep Results" toggle from search & compare view
Persists "reviewed" checkboxes in comparisons

* Adds secondary remote match and improves branch resolution

* Updates branch format to {owner}/{repoName}:{branchName}