Add component types which a process is hosting into the proc memstats

When taking the snapshot of the memory usage of each process, log
what type of component this process is hosting, i.e., activities,
broadcast receivers, etc.

Bug: 233822891
Test: dumpsys activity -a
Test: statsd_testdrive 18
Change-Id: I04bfc53f87b67bbb6a765f13c8a010bb0d640135