Engine: UI: Lifecycle Environment Paths UI

This PR contains a couple of commits to provide a new page for managing 'Lifecycle Environment Paths'.

This includes:
- ability to access the new page from Content -> Lifecycle Environment Paths (navigation). This will not be necessary once we have a single nav; however, it can be used in the meantime.
- ability to create/review/update/delete environments from the new page

A couple of things to be aware of:
- This PR does *not* include tests.  Those will be worked on in parallel and added to the PR as a separate commit.
- While working on the page, found that attempting to use the legacy path selector didn't really fit well for this page.  The reason being it wasn't written using angularjs and was lacking several things we needed to accomplish with this page.
-  Based on our initial UI design discussion, the goal was not to overcomplicate the page.  As a result, it is purposely not a 'nutupane' page; however, it is written using angularjs.
; however, I wanted to send this now to get some initial feedback.