[Docs] Destination of Help and Visit Homepage links in the Administrator

[PBRichardson]

Description

In the Administrator, the Help link currently points to the GH discussions page, whereas there is much more help available from other sources such as Discord. In addition, as the user may be better served by reviewing documentation than asking a question in a forum, it would seem better if this link pointed to the GH docs site which, even in it's fairly nascent state, is a better resource than the discussions page.

Separately, in the Administrator, the Visit Homepage link goes to the OIE/engine repo whereas, again, the GH docs site would seem a better location.