Last revision before the introduction of the nonfree "Ambient SDK"

We received a report by Tad on the Replicant mailing list that all
Replicant releases contained a nonfree library called "Ambient SDK"
that came from CyanogenMod.

As explained by Tad, when LineageOS forked CyanogenMod, only part
of that library was removed, and so we ended up with it as
Replicant 6.0 is based on the first LineageOS release (13.0).

Tad also pointed us to commits in DivestOS Mobile to remove that
nonfree library. In many cases, these commits simply revert the
affect git repositories to before the introduction of this nonfree
"Ambient SDK" library.

Belgin then investigated how to best remove it in Replicant 6.0 and
found out that simply reverting the commits was too much work.

So instead Belgin solutions combines many strategies to make it work
with the current Replicant 6.0 source code:
- Some repositories are to be reverted to the revisions before the
  introduction of the "Ambient SDK". This is what this tag is about:
  it enables people to more easily understand that the commit tagged
  is the last revision before the introduction of this "Ambient SDK".
  The commit hash to be tagged were provided by Belgin in the Replicant
  mailing list.
- In several repositories some commits were also reverted to remove the
  support for this "Ambient SDK".
- As the code evolved since the introduction of the Ambient SDK, some
  repositories had to be fixed as well to still compile without it.
- The Android.mk that downloaded the "Ambient SDK" from maven packages
  repositories was also removed.