Closes#11073
In the provided link, SWF params give up to 720P, and VideoConfig
gives 1080P for both best and bestvideo. I guess all Facebook videos
supports HTML5 now, so I remove the old detection for SWF params
The example in #10813 requires TV provider authentication in Firefox,
while youtube-dl can download it directly with an US proxy.
I'm not sure whether the mgid fix is cmt-specific or it applies to all
mtv-based sites. I keep it in cmt.py until similar patterns are found in
other websites.