Refactoring... lots of things

Adding BT pre-flight test that include raising bt logging to 5
Moved all callback strings to bt_test_utils so there is no
need to redeclare them in every file.
Removed all string joins and changed them to format.
Changed most handle events to pop_events.
Modified documentation in BeaconSwarmTest to be accurate.
Removed the 4 second timeout between testcases in FilteringTest.
   The actualy issues is most likely due to a bug in setting
   advertising data. Need to investigate,
Removed BackgroundScanTest from the sanity suite since there
was a change in the flow of the testcase. Needs more work.
Removed print statments in BackgroundScanTest.
Added hci timeout stress test to BleStressTest.
Speed up GattOverBrEdr tests by getting the mac address in
class setup instead at each testcase.
Fixed reboot function as it only waited
5 seconds and continued and fialed. Now it waits for device to boot.
Separated GattFacade into GattClientFacade and GattServerFacade.
Disable background scanning as a part of the general test class
setup. This was causing various negative testcases to fail
especially in opportunistic scan related testcases.
Fixed ConcurrentBleAdvertising testcase

Bug: 22921103
Change-Id: Ie1453fcfb9b2c3dea36679988501d3fcab568690
3 files changed