`useDefineForClassFields = false` is apparently required for Lit

- adds lit components
- exposes webview in WebviewViewBase
- adds pointer cursor to enabled buttons
- adds custom events support to DOM utility

Giving up on better else/catch/finally formatting -- can't fight anymore
Switching to tabs for better accessibility
https://twitter.com/sh4na/status/1146837957200027648

Splits App into AppBase & AppWithConfigBase for impl of new webviews

Adds bundle analyzer
Adds circular deps analyzer
Switches to es2018 output
Removes many circular dependencies

Changes from out to dist
Adds size-plugin (commented out for now)
Adds image cache to improve bundle performance

Uses import() for copy/paste and tmp

Adds webpack for bundling (disabled for now)
Uses tslib to bundle less duplicate code

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`)

Fixes lint issues

Fixes all the compile/lint issues

Removes typings (using npm instead)
Fixes some promise catches