Support for choice of resolver and/or Web server

[jacob.salmela]

This is a parent feature request, which may be implemented via these two requests:

Check for existing DNS server during installation

During installation, check for an existing DNS or HTTP daemon and then determine the best way to proceed with the install. Some distro's have another webserver running, or possibly a master daemon like connmand that have their own DNS resolvers. Check and warn that this will not work very well. Referenced from Ubuntu - No DNS queries · Issue #1089 · pi-hole/pi-hole · GitHub

Check for existing webservers during installation

Transporting a feature request from GitHub to make it votable here. Was having this issue, and it was of course resolved by removing the non-folders in /var/www/html/. This should be checked during installs and upgrades and the user warned or something.