Remove client configuration files when uninstalling WireGuard

[dvershinin]

Got seemingly invalid client config by these steps:

• Run the script, add client with name example
• Remove WireGuard using script menu
• Run the script again, specified same client name example

The resulting file has.:

[Interface]
...

[Peer]
...
[Interface]
...

[Peer]
...

[angristan]

Perhaps we need to clean the client files during removal of wireguard.

[angristan]

I've renamed the issue. This could be added as an option to the uninstall process.