enh: setup-gpg.sh: create additional backup signing config with --generate

[docwalter]

#243 allows for signed backups, but setup-gpg.sh --generate only creates signing config for session recording backups so far. With this code, setup-gpg.sh generates a config snippet for signing configuration backups, too.

Since the signing key passphrase can contain arbitrary special characters, it is wrapped in single quotes and any contained single quote ' is escaped as '\''. Tested it successfully with a several generated signing key passphrases, including ones with single quotes.

Signed-off-by: Philipp Walter p.walter@infoserve.de

[speed47]

You're right, that was a missing part of the setup script indeed.

Thanks for your contribution and testing, lgtm :)