About: Update template.
Membership.html: Remove unneeded template.
Base: Remove membership from base.
About: Update template.
Membership.html: Remove unneeded template.
Base: Remove membership from base.
Merge hotfix-condense-about-membership-page (#58) into master

Condense about and membership into one page.

The pages feature such a small amount of text that we're better off with
one page that cleanly organizes the content.