Adds templating support to explorer views

Moves annotation messages from formatter to annotations
Moves icons into dark/light folders

Adds all-new, beautiful, highly customizable and themeable, file blame annotations
Adds all-new configurability and themeability to the current line blame annotations
Adds all-new configurability to the status bar blame information
Adds all-new configurability over which commands are added to which menus via the `gitlens.advanced.menus` setting
Adds better configurability over where Git code lens will be shown -- both by default and per language
Adds an all-new `changes` (diff) hover annotation to the current line - provides instant access to the line's previous version
Adds `Toggle Line Blame Annotations` command (`gitlens.toggleLineBlame`) - toggles the current line blame annotations on and off
Adds `Show Line Blame Annotations` command (`gitlens.showLineBlame`) - shows the current line blame annotations
Adds `Toggle File Blame Annotations` command (`gitlens.toggleFileBlame`) - toggles the file blame annotations on and off
Adds `Show File Blame Annotations` command (`gitlens.showFileBlame`) - shows the file blame annotations
Adds `Open File in Remote` command (`gitlens.openFileInRemote`) to the `editor/title` context menu
Adds `Open Repo in Remote` command (`gitlens.openRepoInRemote`) to the `editor/title` context menu
Changes the position of the `Open File in Remote` command (`gitlens.openFileInRemote`) in the context menus - now in the `navigation` group
Changes the `Toggle Git Code Lens` command (`gitlens.toggleCodeLens`) to always toggle the Git code lens on and off
Removes the on-demand `trailing` file blame annotations -- didn't work out and just ended up with a ton of visual noise
Removes `Toggle Blame Annotations` command (`gitlens.toggleBlame`) - replaced by the `Toggle File Blame Annotations` command (`gitlens.toggleFileBlame`)
Removes `Show Blame Annotations` command (`gitlens.showBlame`) - replaced by the `Show File Blame Annotations` command (`gitlens.showFileBlame`)

Adds blame toggle to the editor toolbar

Cleaned up the blame hightlights (wip)