media-capture: set Baseline status

[ddbeck]

We probably need a note field now, to explain why this will (never?) be non-Baseline.

media-capture is an interesting feature: it's implemented in, and arguably more targeted at, mobile browsers, and using the HTML capture attribute on desktop should not break anything (using the IDL attribute may though, since it's going to be undefined).

In a way, html.elements.input.capture could be seen as having a high baseline status. I don't suggest doing that. That just seems like a good candidate feature for statuses beyond baseline that might be worth calling out to developers: you can use the attribute everywhere, just be aware that it won't do anything on some platforms.

Originally posted by @tidoust in #461 (comment)

[foolip]

@ddbeck can you add in the notes you think we should have here? We can just add it to the schema, and a notes field which is either a string or an array of strings (like BCD) seems sensible to me.

[foolip]

#825 will take care of this.