BUGFIX: Make OPENPGPKEY records functional.

[gucci-on-fleek]

I'm unable to get DNSControl to create an OPENPGPKEY record that gpg or openpgpkey will accept. From what I can tell, it looks like DNSControl always corrupts or misinterprets the input, meaning that there is no possible input that will produce a valid result. But if I build DNSControl with this PR applied, both gpg and openpgpkey accept the OPENPGPKEY record without any complaints.

I'm probably just misunderstanding something though, since I wouldn't expect for the current code to not work at all.

I've also expanded the OPENPGPKEY documentation, and fixed a small bug with the --debug argument. Full commit messages:

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BUGFIX: Make OPENPGPKEY records functional.

Previously, #3718 introduced support for OPENPGPKEY records. However, that PR assumed that the OPENPGPKEY key data was hex-encoded. RFC 7929 §2.3 states that when in "Presentation Format", OPENPGPKEY record data must be base64-encoded instead. Since most hex-encoded data can be parsed as base64, DNS providers would not reject a hex-encoded key, but they would instead parse it as base64, leading to a corrupt result.

Additionally, the previous PR also unconditionally lower-cased the key data, making it impossible to use base64-encoded keys. Once again, lowercased base64-encoded data can usually be parsed as base64, but the result will be corrupted.

This current PR fixes both of these issues by instead treating the key as base64-encoded data, and by no longer lower-casing the key data. To maintain backwards compatibility with existing hex-encoded keys, the code attempts to detect keys that appear to be hex-encoded, and decodes them as hex before re-encoding them as base64.

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BUGFIX: Make --debug not print the version.

Currently, using the --debug command-line argument just prints the DNSControl version and exits. This is because the long option --debug is mapped to the short option -v, but -v is used for --version, so the parser gets confused. This commit remaps the long option --version to the short option -V, which prevents the parser from getting confused and makes --debug work again.

[tlimoncelli]

Hello friend!

Thanks for spotting this and making a PR to fix it.

The new encoding makes a test fail. Can you please take a look at this?

$ cd ~/git/dnscontrol/pkg/js
$ go test ./...

# Test 056 fails.  The actual results are in parse_tests/056-openpgpkey.json.ACTUAL

# If they are correct...
$ cp  parse_tests/056-openpgpkey.json.ACTUAL parse_tests/056-openpgpkey.json

$ cd ../..
$ bin/generate-all.sh