Add stats logging to ServiceManager and NPMS

ServiceManager:
- Do an event log every N getService() calls with total time spent
in getService().
where N = 100 for core UIDs and 200 for other apps.

- Do an event log if getService() takes longer than N ms.
where N = 10 for core UIDs and 50 for other apps.

... with some extra throttling.

NPMS:
- Do the basic "stats logger" log for updateNetworkEnabledNL() and
isUidNetworkingBlocked()

This CL also enhances StatsLogegr so it now can show the slowest call
and the max # of calls per-second.

Bug: 77853238
Test: Manual test:
- Insert a SIM card
- Set data limit
- toggle airplane mode
- toggle wifi
- toggle mobile data

Then
- "dumpsys netpolicy" and "dumpsys activity processes" and check the stats
- also check "adb logcat -b all | grep ' service_manager'"

Change-Id: I5789541063f95d0eac501189816c8604a4571ba0