uninstall script does not remove packages

[ybornat]

Subject of the issue

The install script (raspap) downloaded and installed debian/rapbian packets. The uninstall script did not get rid of them.

Your environment

• Raspberry Pi hardware : Pi 3B
• Raspbian version : Stretch Lite
• Followed the project prerequisites? (Y)
• Checked the project FAQ? (Y)
• RaspAP Quick Install
• Using default configuration? (Y)
• Simultaneous AP and managed mode? not relevent
• Other software or services running with RaspAP? yes but not related

Steps to reproduce

quick install on a fresh raspbian, then unsintall using the provided script

Expected behavior

I expect all packets required and installed by raspap to be removed from the system

Actual behavior

these packets are still on the system

[billz]

Added a prompt to optionally remove packages installed by RaspAP.
A user could install these packages separately (ie., outside of this project) so giving them the option to uninstall is the right approach here.