Support bluetooth not using MultinetworkPolicyTracker

This required advancing the IpManager to IpClient refactoring
(Bluetooth used IpManager and friends). Most importantly, the
Bluetooth code used WaitForProvisioningCallback, so this is
moved into IpClient proper now. Also: some more renaming
cleanup.

Test: as follows
    - built
    - flashed
    - booted
    - runtest frameworks-net passes
Bug: 62476366
Bug: 72663849

Merged-In: I5e5b2c59ad3ea9ad574e8e683bcab3b09cfe0791
Merged-In: I89b45310181d952129fb2294db63654da9b4057f
Change-Id: I9eee2a9d5c31cdd48a054a7edc3403584efb1864
(cherry picked from commit 8d1fe54b)