Switch everyone over to new BwdServer

[pbiggar]

Making a plan for how to switch everyone over.

Issues that MUST be solved first

• httpclient issue (HttpClient::getv5 "https://google.com" {} {} fails with "utf8 decoding error" #3680)
• sqlcompiler issue (Fix "operator does not exist: integer = text #3699)
• getting 500 on big user, unclear why #3710

Issues that SHOULD be solved first

• possible unicode bug (FuzzTests Failing on Bad Unicode Strings #3649) - (not a big deal)
• possible jwt bug (JWT JSON parser doesn't support NaN well #3662) - (doing it later)
• hsts (Add strict-transport-policy header on BwdServer and ApiServer #3677)
• compression (Re-add compression to BwdServer #3664)

Issues that give us confidence that it will be fine

• FSHARPONLY vs OCAMLONLY
• performance (test performance (speed + latency) of new services #3624) (probably ok here)
• libstaticassets security (Make libstaticassets go through the socks proxy #3683)
• code coverage (Run F# backend against coverage tool #3688)
• fuzzing (Fuzz all pure functions #3556)

How to actually go through the migration

• make list of people with more than 100 requests to BwdServer per week
• draft email
• notify them by email
• wait a few days, see if any volunteers come up
• starting from the smallest, switch them over (possibly a handler at a time for larger users)
• watch for changes in status code, latency, response size, rollbars
• wait a few days for reports, etc
• switch the DNS

[pbiggar]

Currently, one canvas breaks on the new thing due to invalid json. One customer has asked to go last.

So we're good to switch over all canvases except those two. That can be done on the current load balancer, but can't be done after we switch the DNS (we're done at that point).

I'm going to start switching the custom domains over (some - mostly ours - have been switched already).

[pbiggar]

Done