Docker container Arm builds

[JakeWharton]

For Raspberry Pis, etc.

External issues:

• Would be great to have an ARM build of this container available plex-auto-trash#1

Projects:

• JakeWharton/docker-mbsync
• JakeWharton/gitout
  • Add Linux Arm support gitout#319
• JakeWharton/hardcover-data-sync
  • Add Linux Arm support hardcover-data-sync#107
• JakeWharton/plex-auto-trash
  • Cross-compile container plex-auto-trash#62
• JakeWharton/plex-orphaned-files
  • Add Linux Arm support plex-orphaned-files#53
• JakeWharton/qbt-orphaned-downloads
• JakeWharton/qbt-tracker-hound
• JakeWharton/qbt-seed-type
• JakeWharton/radarr-folder-fixer
  • Add Linux Arm support radarr-folder-fixer#28
• JakeWharton/singular-solution
  • Add Linux Arm support singular-solution#120