[Feature Request] Present a "Create Ed25519 keypair" button if missing

[Mannshoch]

In my network I use Tinc 1.0
So I have on the generated onfigs no Ed25519 keypair. Many entries in tinc.NETNAME.log shows the entry:

Error Reading private key file ....
Create an Ed25519 keypair with "tinc -n . generate-ed25519-keys".
support for SPTP disabled

[pacien]

If you only use tinc 1.0 everywhere else, you can disable the 1.1 protocol and the use of Ed25519 keys by putting ExperimentalProtocol = no in tinc.conf.

Missing Ed25519 keypairs can be generated on the device from the command line tools from ADB or any terminal emulator by running $tincctl -c $confdir/$netname generate-ed25519-keys with $tincctl and $confdir set as displayed in the app's configuration screen.

I don't think that adding a shortcut for this in the GUI would be commonly useful, as importing an existing configuration implies having access to those command line tools used to generate the missing keypairs. Contributions are nevertheless welcome.