new debugging function - unset variables

[rs232]

It would be very good to have a new section under debugging to unset certain part of the config.

E.g.

remove NVRAM OpenVPN client1
remove NVRAM OpenVPN client2
remove NVRAM OpenVPN client3
remove NVRAM Wireguard

etc.

This could be centrally on the Debugging page and/or on the relevant pages themselves.