Add video support from facebook to matrix

[Grenadingue]

Current master behavior

• When a video is sent from Facebook, nothing received on matrix client
• Debug log: matrix-puppet:facebook Unknown attachment type video

Current branch behavior

• When a video is sent from Facebook, video is received on matrix client
  • is viewable (if ffmpeg is installed in bridge's environment)
  • and downloadable

What changed?

• Recognized video attachment from Facebook, set its metadata then send it to matrix server
• Added ffmpeg dependency in Dockerfile and README.md

What happens when ffmepg is not installed in bridge's environment?

• Warning log: matrix-puppet:Base:handleThirdPartyRoomMessageWithAttachment:info Couldn't get video dimensions. Is ffmpeg installed?
• On matrix client the video only appears as a downloadable file: no preview shown (source)

[Grenadingue]

Force pushed to update invalid commit message

• from: Recognize video attachment from Facebook to Matrix as multimedia instead of plain file
• to: Recognize video attachment from Facebook to Matrix as multimedia

[Grenadingue]

No news since two months..

Bump @nr23730 @thomas-profitt

[Grenadingue]

Thank you :slightly_smiling_face: