Improve power stats formatting

Instead of manually implementing the dump/toString logic
for different power components, use a generic mechanism.

Bug: 323970018
Test: atest PowerStatsTestsRavenwood && atest PowerStatsTests
Flag: com.android.server.power.optimization.streamlined_connectivity_battery_stats
Change-Id: I12f19f3c772a04b4cd6def0a4af1cf919cdc57d4