apexer: add apex_manifest.pb

apexer adds apex_manifest.pb as well as Q-compatible json and R+ json.

apexd on Q can't understand newly added properties in
apex_manifest.json, which prevents from installed APEX packages built
with new properties.

apexer accepts three of apex_mainfest(.json, _full.json, .pb) from
commandline, and then put them in the apex container and image in it.

Bug: 143654022
Test: m -j
Change-Id: I8752b0c21af747be6fc5c3a04d1cb114d789c77e
6 files changed