Add installed jre

[scottresnik]

I added functionality to specify additional JRE's to be included in the workspace.

[nedtwigg]

For future reference, you can just run gradlew spotlessApply and all the formatting issues will be resolved, including line ending problems. As-is, I can't tell what these commits actually do because of line ending and formatting mixups. Do you mind running spotlessApply and squashing them all into one? If you don't know git-fu, I can do it for you.

[nedtwigg]

Sorry, should have opened with "looks like a great feature!". I'm excited to merge it in :)

[scottresnik]

Missed spotless on the last commit. Squashed the formatting commits. Left the meat. I can squash further, if desired.

[nedtwigg]

Thanks a ton for the great contribution! A couple questions:

• How can I credit you in the acknowledgements? Scott Resnik? Would you like me to link to your github, twitter, elsewhere?
• Shall I release this as 3.5.0, or is there more coming down the pike that you'd like to be included?

[scottresnik]

• RE: acknowledgements: I guess my name + github is fine. Just glad I could make a contribution to a useful plugin.
• RE: 3.5.0: Ship it :).