Add modules to build a non-pre-installed version of shim apex

This apex will be used in CTS tests to verify that an apex can't be
installed if there is no pre-installed version of it in.

Since I was there, also updated README.md.

Test: m com.android.apex.cts.shim_not_pre_installed
Bug: 128625955
Change-Id: Icf678a967d9d79a1b5ef3370584aa3ba5c022b54
3 files changed
tree: 8ffe20b7475be803b99c80a89e525d77d2ec647c
  1. apexd/
  2. apexer/
  3. proto/
  4. shim/
  5. tests/
  6. CleanSpec.mk
  7. OWNERS
  8. PREUPLOAD.cfg