Add ability to skip plugin execution

[Aloren]

No description provided.

[coveralls]

Coverage remained the same at 86.976% when pulling 5a96aab on Aloren:feature/add-ability-to-skip-execution into 08e214b on alainsahli:master.

[cstettler]

Thank you @Aloren for this contribution. While I can see the use case for skipping the Maven plugin execution (conditional build steps), I am not sure about adding the same support for the Docker-based publishing.

In fact, your current implementation would not use the provided SKIP environment variable in the Docker-based publishing at all, as under the hood, the Docker-based publishing does not use the Maven Mojo, but the AsciidocConfluencePublisherCommandLineClient.

Anyway, if you agree with me, I would suggest to restrict the skip parameter to the Maven plugin execution only.

[Aloren]

I am not sure about adding the same support for the Docker-based publishing.

this was my initial thought as well. i will remove it, added it just in case you would like to have all parameters to be available in container as well.

Docker-based publishing does not use the Maven Mojo

Sorry, my bad. :(

Anyway, if you agree with me, I would suggest to restrict the skip parameter to the Maven plugin execution only.

agree, no problems

[Aloren]

rebased onto master and fixed

[cstettler]

Merging PR to pr/aloren/feature/add-ability-to-skip-execution for integration into master