[PASSPOINT] Add metrics to determine deployment/avail of Passpoint

Add metrics which will help determine Passpoint availability in the
wild. The metrics measure the percentage of time a Passpoint network
is visible to user - by collecting historgrams of observations per
scan result.

(cherry-pick of commit c8fdb198d47d30ea9618eff685d6a830e5ed06d4)

Bug: 66951771
Test: unit test
Change-Id: I80af113f120515d86b2b6adb3e44ce37e97d5441
Merged-In: I51e05e9a075259544008107810c4489e8111cfcd
2 files changed
tree: 36c49ecbad9e47fcb285a2a9df24ba41fce67368
  1. service/
  2. PREUPLOAD.cfg