More than one user with Manager or Admin permissions can be created from UI

Patched some security holes with GetUser and UpdateUser, did some minor cleanup

Merge from development branch

Changed available actions done by an admin to itself: admin can no longer remove itself from users list, admin can no longer change its user type to manager.

User control patch

Revert "User control patch"

Revert "Merge from development branch"

Updated wgui.service to only apply changes, that were made to clients. Not fully tested, could cause issues with wg-quick specific options.

Changed wgui.service to call additional restart-wg.sh file.

Created wireguard restart script, which compares wg0.conf part between [Interface] and first peer with previous version for changes, and, if there is any - restarts whole wireguard, if the only changes are done to peers, it calls "wg syncconf", eliminating client disconnection after pressing apply config problem.