Add cog setup scripts

This script has the following functionality:
1. Sets up the `out` symlink to point to a default location on disk
2. Copies RBE binaries outside Cog (temporary fix for build stall problem) - b/289391270
3. Exports ANDROID_BUILD_ENVIRONMENT_CONFIG variable to point to googler-cog.json file. This file will be available in aosp-main-with-phones and goog/main and downstream branches.

TESTED=ran the script within and outside the Cog workspace to test it.

Bug: b/295053716
Change-Id: I59cd6d2d5f954be6f7e4ecd7d64de1e63e51b72e