Summary:
Implement audio preview using web ui.
Add new blob handler for audio files.
Test Plan:
1. Upload browser compatible audio to perkeep
2. Navigate to web UI
3. Play audio without leaving perkeep ui
4. Pause audio
Before:
Audio cannot be played using web ui
After:
Compatible audio can be visually identified by the volume icon instead of the default file icon.
Hovering over the audio blob shows a play button.
Click the play button to start playing the audio.
Click the pause button to stop playing the audio.
Issue: #202
Change-Id: Iab8ee4a339f44178992e11e02232d480cd534b3e
Omar Chehab