Android O MR1 IOT Release Smart Display r8 (OIM6.190107.025)

Android O MR1 IOT Release Smart Display r5 (OIM4.181017.001.A7)

Migrate libmojo repository into libchrome, part 2.

This CL moves following files.
- .gitignore
- Android.bp is merged into libchrome's Android.bp.
- base/android/*
- build/* except build_config.h which is exactly same with libchrome's.
- ipc/*
- mojo/*
- soong/* into libchrome_tools/
- third_party/{catapult,jinja2,markupsafe,ply}/*
- ui/gfx/{geometry,range}/mojo/*

Then removed following files:
- Android.bp
- CleanSpec.mk
- build/build_config.h

And added README.md to notify the migration.

Bug: 73606903
Test: Built locally. Ran on DUT.
Change-Id: I94aa1b43ff0854f48f30fdf03025bd1c8a346038