Makefile: remove unneeded MONITOR_PORT config
Squashed 'vendor/adafruit-vs1053/' content from commit 9e52b4f

git-subtree-dir: vendor/adafruit-vs1053
git-subtree-split: 9e52b4f705014864e483374da1303b535b3fe982
Merge commit '476c76b5bf946df66c0dfcc9740c01ebaa6186e7' as 'vendor/adafruit-vs1053'
Play a little startup sound on setup()