Initial sencha support

Builds & runs a release firmware image. Enabling built-in audio
data allows demo app to run further but it hangs (likely in the
i2s emulation where it also hangs for nexus).

TODO: gdb support needs work, stock gdb complains:

  warning: while parsing target description: not well-formed (invalid token)
  warning: Could not load XML target description; ignoring
  warning: multi-threaded target stopped without sending a thread-id, using first non-exited thread
  Remote 'g' packet reply is too long (expected 132 bytes, got 264 bytes):...

Bug: 330742177

Change-Id: I3d2565572313725765b91bac55f93cb0a30babb6