GD-Storage: Integrate legacy and GD stack with new GD storage module

* Reposition shim layer at the btif_config interface
* Implement shim layer between legacy stack and GD stack
* Get rid of existing storage/legacy* replated implementations
* Add os:ParameterProvider to supply config file paths that are
  different on host and Android

Bug: 157533831
Test: atest bluetooth_test_gd, manual
Tag: #gd-refactor
Change-Id: I87db6b3687e252999bfe5459d11b0ee89aac373f