Revert "Bug 906096 - Add some Gaia workaround to ensure the new IME framework continues to work in Firefox Nightly" for gaia unit test failures

This reverts commit dd56a2ca87d249095cc16c417518ce1f105e90eb.
Revert "Bug 856910, Bug 893557 -" for gaia unit test failures

This reverts commit 3e8f5b3f231033a7a9d4778d24cb3192159837a4.
Revert "Bug 856910 - Add MVVM pattern in settings app. r=evelyn" for gaia unit test failures

This reverts commit 21f40ee8e06106c1190dfc4fd3ed959dfe4bb08e.
Revert "Bug 858383 - [Keyboard] Integrate the new keyboard manager with switch" for gaia unit test failures

This reverts commit c602ea3fd92e8942704267773f961b77c61e7841.
Revert "Bug 816912 - Keyboard Manager to support 3rd-party keyboard" for gaia unit test failures

This reverts commit a08c63b48abbb8c261de649a246c2b2530111f6e.