refine sponsor views and other minor content updates

* closes #1218 - create sponsor page with thank you statement, also include diversity statement for grant
* closes #1325 - create rows for sponsor page
* closes #1326 - build tiered sponsor structure into right sidebar
* closes #1332 - add page for sponor donations, link to from contact page
* closes #1335 - homepage/abstract submit content updates
Merge branch 'sponsor_view_cleanup' into dev