"Applications based on Readium" needs updating

[rkwright]

The "Applications based on Readium" page is very out of date. Some apps no longer exist, some have changed and there are apps out there not listed.

[HadrienGardeur]

I'm not sure that this is worth tracking. With a BSD-3 license it's going to be very hard anyway.

I think we should remove this page and eventually replace it with testimonials from selected members.

[rkwright]

@HadrienGardeur +1 to the idea of "testimonials". Don't know if people will want to do it. But maintaining the list of apps was a lot of overhead so I am fine with it going away.
Will leave this issue open to track this idea.