Few USB-related updates

Finally... don't have to sync external mics

Supports USB mic (at least 1, Lavalier) audio merged into mp4 video from h264

Also added mass storage transfer (don't have to use SFTP eg. FileZilla)

And with Delete All Files again don't have to SSH into it to remove files

Videos and PRs

https://github.com/jdc-cunningham/modular-pi-cam/pull/17

https://github.com/jdc-cunningham/modular-pi-cam/pull/18