License text, setup instructions, and support info do not need to be
duplicated into every README, since they're already in the top-level
README. They were originally in each sample because the samples used to
each be separate Android Studio projects with different requirements
that could be checkout out independently in Android Studio. This is no
longer the case.
Most of the docs also included text along the lines of "This sample uses
the new Android Studio with CMake support", which hasn't been new since
2015, so doesn't really need to be said.
The prerequisites were mostly not true. Android Studio is not required
for any of this. Cloning the repo and running `./gradlew build` is
sufficient to build all the samples. They also were not being kept
up-to-date at all, since they mostly said "Android Studio 2.2 or newer",
which was definitely not true. I'm not what the oldest version of
Android Studio that will work here is, but I don't actually test
anything but the latest so claiming anything otherwise is just
misleading.
I haven't pruned or edited any of the real content of the docs. I'm sure
there are plenty of edits to be made there and a lot of expansion to do,
but those changes will be less mechanical and will happen separately.
Move build status badge down into the "Build and Run" section to avoid
it being pulled in as part of the repository description by automation.
Bug: 350055171
Some of this is quite old. Links to YouTube videos from 2015 and
websites that don't exist any more aren't so useful. Update and
rearrange.
Still lacking is an ARCHITECTURE.md that explains the repo layout. I'll
do that next.
