Parse notes to render images and videos

[sondreb]

Posting on the profile should support some basic formatting such as rendering videos, links and photos.

For security reasons, these are the only features allowed initially.

• If known video-site, render embedded video.
• If known file extension, render either music or video player (mp3, mp4, etc)
• If known photo extension, render as image in-line with click to show full size.

Other links should link to target _blank.