🔨 Improvements

Initial multi-root support in #121
Adds support for CodeChecker 6.22's automatic compilation database detection. If no compilation database is specified, and there is none in CodeChecker's output folder, the extension will use CodeChecker's autodetection (for 6.22 and above). For 6.21, and the mentioned cases, the behaviour remains the same.
Notifications overhaul in #116
Added a sidebar view to show past notifications. The notifications actions can still be executed through the sidebar, even if the user disabled pop-up notifications.
Notifications for the executed processes in #120
Added notifications for adding CodeChecker log and analyze commands to the queue, and then executing them.
They are mainly displayed on the sidebar, and there are actions for killing the process or removing them from the queue.

🐛 Bug fixes