This reverts commit ad7e861d.

Fixes #3068

This commit adds the --user-data-dir argument which allows a custom data dir
for Chromium's user data. This is useful when running as root on Linux since
the root user does not have read or write permissions for the ~/.config/Code
dir.

Part of #3068

Linux update notifications

when printing commands for keybindings, skip those that declare arguments and those that start with `vscode.', fixes #4915.

Joh/webview