Allow manual removal of /library/calibre-web/config/app.db for easier resetting of Calibre-Web app settings (without damaging your e-book collection metadata in /library/calibre-web/metadata.db !)

[holta]

To complete this resetting of Calibre-Web settings, (1) delete or move your pre-existing /library/calibre-web/config/app.db aside (2) then proceed as follows:

cd /opt/iiab/iiab
sudo ./runrole --reinstall calibre-web

[holta]

This PR is tested to work on Raspberry Pi OS and Mint 20.3 from Jan 2022.

ASIDE: 10 days ago Calibre-Web worked on the Ubuntu 22.04 pre-release from that time, but there appears to be a (hopefully transient?) VENV failure with the latest Ubuntu 22.04 pre-release:

TASK [calibre-web : Download Calibre-Web dependencies (using pip) into python3 virtual environment /usr/local/calibre-web-py3] ***
fatal: [127.0.0.1]: FAILED! => {"changed": false, "msg": "Unable to find pip in the virtualenv, /usr/local/calibre-web-py3, under any of these names: pip3, pip. Make sure pip is present in the virtualenv."}

Tangentially Related:

• IIAB installs fail on Ubuntu 22.04 (ETA 2022-04-21) due to "No package matching 'usbmount' is available" #3126

[holta]

Also tested successfully on Ubuntu 20.04