Donate page

[stumbo]

@pamoroso I took your start and made some modifications.  I think this encompasses what we talked about on Wednesday along with the latest comments.

1. The Donate page is now a separate page.  It exists in the Medley Interlisp Project hierarchy at the same level as Get Involved.
2. The Get Involved page refers to the Donate page and the donate contents on that page have been moved into the Donate page
3. Some cleanup of the page. 

I decided against putting a donate button on the bottom of every page.  That seems like a little too much

[pamoroso]

Thanks, it looks good to me.