Fix #4191 make websockets work in angular in parallel with http

[robnagler]

TODO:

• http prefix
• promoting to email user (need to use $http)
• Fix authState redirects to root if user dir not found #6205 authState exception
• Fix change srunit to use websockets when enabled #6119 websockets in srunit

Depends on radiasoft/pykern#388

[robnagler]

• This does not including caching of frames. It was pretty fast as is so good enough for using on alpha.
• Logging is different than tornado requests. It logs the start and end of the requests, because we have different information. The entries are sequence numbers and can be tracked.
• Includes some refactoring of requesting downloads, but those are the same (GET) because they don't happen often.

[robnagler]

@e-carlin this is ready for another review. I think it could be merged (only on in dev). The next big issues are caching frames and pub/sub for runStatus. These should be separate concerns. The former is necessary for a prod release but not the latter.

One question I have is how frequently should the UI try restarts on the websocket. I think polling is fine, since it's a lightweight request. There might need to be a user alert in the UI that connection has been interrupted from more than, say, 30 seconds (server restart).

[e-carlin]

Only one small comment on a comment.

All of my click around testing worked. Obviously there are counltess cases I didn't manually test so it would be good for other people to click around edge cases in their apps.

One general comment, I find myself frequently opening the developer tools network tab to view what requests are made and what the content of those requests are. With websockets and a binary protocol that now doesn't work. What about adding a pkdc to parse_message and websocket_response that allows one to dump the message (with associated uri, seq num, etc)?

[robnagler]

One general comment, I find myself frequently opening the developer tools network tab to view what requests are made and what the content of those requests are. With websockets and a binary protocol that now doesn't work. What about adding a pkdc to parse_message and websocket_response that allows one to dump the message (with associated uri, seq num, etc)?

#6250