Contact email on About Us page -> support@

Signed-off-by: Daira Hopwood <daira@leastauthority.com>
Change valid_email text to be applicable to both existing and future products.

Signed-off-by: Daira Hopwood <daira@leastauthority.com>
Tweak to pricing text.

Signed-off-by: Daira Hopwood <daira@leastauthority.com>
Add open-source licenses (same as Tahoe-LAFS).

Signed-off-by: Daira Hopwood <daira@leastauthority.com>