Add customtabs support lib to extras/android/support/

Currently the only way to get access to customtabs library through
download m2repository and using the aar file whereas all other
support libs are also present in extras/android/support/ with
the corresponding resources and jar file.

This adds the jar and manifest to the corresponding folder to avoid
the confusion to developers.

This is relanding
after it was reverted due to not having the corresponding

Change-Id: I21969994e1dd0bb4f9abbfa395cf284e3cfc396d
2 files changed