Until this can be implemented properly

Adds types for comparison uri methods

Adds get previous line comparison uris for GitHub
Improves perf of get previous comparison uris for GitHub
Replaces HEAD usage with proper revision for GitHub
Renames comparison uri methods for clarity

Providers can now choose how to handle editor contents blaming
Simplies "commit" line model to just have line & originalLine
  - Not really accurate for log parsing, but close enough
Adds forces line blame to improve performance

In favor of the same options as buttons on the commit item itself

Moves scm git uri creation to local git provider
Removes relative path usages from GitUri
Adds commit.findFile overload for a uri

Adds separators to better group commands
Adds isPushed to commits

Moves formatting globals to the container

Adds authors filtering to commits

Splits get commit branches into 2 methods

Consolidates into a single method call

Improves commit tooltips

Uses new log parser for contributors & refs
Removes shortlog references

First pass at converting "blame" commits into a unified model

Adds changes diff for first commit changes

Since we are using native date formatting the formatter abstraction is no longer needed