Bug 1075306 - Implement InputWindow (inherits from AppWindow)

- Instances of InputWindow replaces those iframes we were keeping in InputFrameManager.
- InputAppTransitionManager has been eliminated, in favor of already-built AppTransitionController that works closely with AppWindow.
- The coupling of KeyboardManager, InputFrameManager and InputWindows shall be resolved in a following bug where we'll implement InputWindowManager.
- Flow of showing/hiding/reusing/switching input apps & layouts has been streamlined.
Bug 1092893 - [System2] Implement BluetoothCore
Merge pull request #25249 from mnjul/bug_1075306_input_window_stage3

Bug 1075306 - Implement InputWindow (inherits from AppWindow). r=zac,timdream,alivedise,rudyl
Merge pull request #25757 from gasolin/issue-1092893

Bug 1092893 - [System2] Implement BluetoothCore, r=alive
Bug 834530 - Import fixes for audible tones, dialtones and tactile feedback from the shared dialer r=drs
Bug 834530 - Make the TonePlayer handle the channel sounds will be played on r=drs
Merge pull request #25119 from gabrielesvelto/bug-834530-emergency-dtmf

Bug 834530 - Improvements to the emergency and dialer keypad touch tones
Bug 1010236 - [Messages] When setting recipients.length, we should rerender only if the length decreases r=julien
Bug 1090962 - Skip steps of gather_debug when marionette session does not exist r=davehunt
Revert "Bug 834530 - Make the TonePlayer handle the channel sounds will be played on r=drs" for failing test on request by zac

This reverts commit 8ceeaf53ef3ec0e2ff8bb3e1f1a6a924609e9e3a.
Revert "Bug 834530 - Import fixes for audible tones, dialtones and tactile feedback from the shared dialer r=drs" for failing tests on request by zac

This reverts commit 0b11e185d48df7093fabc99925fc4c47ceba141a.
Merge pull request #25771 from zacc/bug_1090962

Bug 1090962 - Skip steps of gather_debug when marionette session does no...
Bug 1092868 - Fix intermittent failing test, add a waitFor when counting app windows r=kgrandon
Merge pull request #25738 from KevinGrandon/bug_1092868_browser_navigate_intermittent

Bug 1092868 - Fix intermittent failing test, add a waitFor when counting app windows