Add custom start dialog with options

Use a custom dialog with options for recording audio and taps, instead
of the standard media projection permissions dialog. Options will not be saved
and both default to off. Since system audio isn't implemented yet the audio
switch just shows the text for microphone audio.

Also updated ongoing notification text to reflect whether audio is being
recorded.

Bug: 147490562
Test: manual, screenshots at https://drive.google.com/drive/folders/1jIyzmPDwt6oxVGAw319awdSafnoz8nmI?usp=sharing
Change-Id: I2b012a6b8b6611c0d6fcada79ed5bdc009e24b17