Enable use of property music.skip for skipping

[runeflobakk]

Did not see myself proposing a contribution to this plugin, but here we are 😆

With @Parameter(property="music.skip") for the skip-parameter in MusicMojo, this enables the troller to subtly disable accidentally blasting the music in the office space while waiting for the trollees to be trolled, while avoiding being self-trolled.

E.g. by using the command:

mvn install -Dmusic.skip

or even set it globally with the MAVEN_OPTS environment variable:

MAVEN_OPTS="-Dmusic.skip=true"

Running mvn help:describe -Dplugin=music -Dgoal=music -Ddetail in a project with the plugin configured will show the following addition to the skip parameter:

  [INFO] --- help:3.5.1:describe (default-cli) @ signering ---
  [INFO] Mojo: 'music:music'
  music:music
    Description: (no description available)
    Implementation: software.xdev.maven.music.MusicMojo
    Language: java
    Bound to phase: validate

    Available parameters:

      background
        Plays the music in the background (non-blocking) If this set to false,
        repeat will be forcefully set to false
    (...)
      skip
>       User property: music.skip
        (no description available)

[hernil]

As a victim, or trollee if you want, I approve of this 🙌

[AB-xdev]

LGTM

Thank you for the contribution :)