[MPH-219] Replace AbstractEffectiveMojo as static util class

[Giovds]

Closes #333

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[Giovds]

@elharo Since this JIRA ticket was originally your request, could you take a look?
@gnodet Can I ask you to review as well, as I know you've been working on the help plugin in the past?

[elharo]

You can't remove existing public API. You need to deprecate this instead.

[Giovds]

Is this an agreement on all ASF repo's? I thought this was mainly for maven-core API's.

I don't know, but do ASF-plugins support extensions of plugin public API's, do people do this? A quick search on GitHub on this class only seems to result in forks.

Alternatively I can e.g. deprecate it and change the implementation to point to the new class.
When will it be removed, and does this require a new ticket?

[Giovds]

Commit 042a98f could be reverted if it's decided to change it. Otherwise, the commit should revert the breaking change.

[pzygielo]

do ASF-plugins support extensions of plugin public API's, do people do this? A quick search on GitHub on this class only seems to result in forks.

My opinion is similar. This plugin is not library, and its API are goals and their parameters. I would not consider such change to require deprecation.

This class being public does not make it public API.

[slawekjaranowski]

exactly - plugin is not library