2553 [path_provider] Create platform interface (cla: yes)

2554 [web] adding a test for e2e web testing. (cla: yes)

2555 [share] plugin: Update gradle version of example for Android (cla: yes, waiting for test harness)

2557 [path_provider] Use platform interface (cla: yes)

2558 Exclude path_provider packages (cla: yes)

2559 [path_provider_macos] Adds example app (cla: yes)

2560 [connectivity_platform_interface] Add ConnectivityResult.unknown. (cla: yes)

2561 Revert “[connectivity_platform_interface] Add ConnectivityResult.unknown.” (cla: yes)

2564 [path_provider_platform_interface] Rename back to StorageDirectory  (cla: yes)