Split package openpgp to make it reusable

[cstamas]

Is your feature request related to a problem? Please describe.
I'd like to reuse openpgp package, but depending on a maven-plugin is a no-no.

Describe the solution you'd like
Ideally a small reusable openpgp library that is used by this plugin as a dependency. Same stands for me, I'd like to depend on new openpgp.

Describe alternatives you've considered
Lift the sources? 😄

Additional context
Maven Plugins are just that: maven plugins and are not reusable as libs. Hence, I myself always tend to keep maven-plugins as "thin" as possible (basically just config + calls into "real thing").

[slawekjaranowski]

Good idea.

There is a Commons OpenPGP project under Apache Commons sandboxes ... we can try to reactivate it
https://commons.apache.org/sandbox/commons-openpgp/index.html

[cstamas]

I'd keep it out of a (dead) ASF project, just do it here.