[Enhancement]: If "Watcher" is disabled in settings, then a manual "Scan" button should appear in the library

[ZLoth]

Describe the feature/enhancement

If a root user wishes to disable the the "Watcher" feature in settings, then there should be a "Scan" button in the library bar so that newly added books to a file system can be read into a library. Otherwise, there is a series of mouse clikcs to go to Settings → Libraries → Scan to read the added books, then click on the library link to go back to the library to make the necessary post-import edits.