Rename "supporter" to "sustainer" in templates and URLs.

Does not rename the models.

Copyleft Compliance: Minor rewrite of strategy & firmware liberation

This rewrite should improve the stand-alone nature of these documents
and allow for better integration with other summary text and
announcements on the website.

Note that they have now drifted heavily from the original formulation
of the items as grant proposals.

Copyleft Compliance: mostly minor fixes to new pgs

These are mostly minor edits (typo fixes, etc.) to the enforcement
strategy and firmware liberation pages that were just added.

The one large change was to replace the first paragraph of the
enforcement strategy page with the full Conservancy description used
previously. The glue text used to shorten it appeared unsalvageable
and it wasn't immediately obvious how to replace it with something
better, so we used the full description instead.

Copyleft Compliance: enforcement strategy & firmware liberation

These two new documents are based on grant proposals for this work.
We are preparing to announce the work publicly soon. This is a first
draft of both documents.