Log broadcast action in statsd's PROCESS_START_TIME atom.

To save statsd space, the string logged is the substring after the last
dot of the intent action string.

Also add enum type field hosting_type_id to deprecate string type field
hosting_type, to save storage space.

Bug: 223225303
Test: statsd_testdrive 169
Change-Id: Ibf2d0c9f3b62c42d51f637b7b9a54c10b5920037