Renanes "Compare x with" commands

Fixes #405 - stops non-repo from showing up in explorer

Removes gitlens.advanced.git setting

Changes rebase & reset terminal commands to apply to all commit nodes

Adds clearing of the user cache on config change
Fixes lint issues and adds some comments

Also allows for vscode undo support for the applied changes

Renames Show Branches and Tags -> Choose from Branch or Tag History...
Changes it to show the revision history rather than immediate executing

Less roundtrips through to the UI on changes for better performance/UX
Also adds "flash" protection to deal with the active editor changing to undefined between changes