* [JENKINS-52822] Add CLI command to enable a plugin

* [JENKINS-52822] Add CLI command to enable a plugin

This adds the ability to enable multiple plugins at once along with their dependencies.

* Add missing license headers

* Clarify javadoc

* Fix copyright

Work was done while at work!

* Improve short description of enable-plugin command

* Improve output of enable-plugin command

* Clarify enable-plugin errors regarding dependencies