HTTP helpers: don't append auth if not using base url

[josephjclark]

Warning about an new antipattern that may be emerging in the new http adaptors

when you do a get, it'll assume you're using the backend and append headers and stuff. But you might be calling another system entirely.

Should the helpers assume a backend? Should there be a different http.get/common.get/util.get?

[josephjclark]

• adaptor should have adaptor specific http helpers. Docs should be clear. Absolute URLs should throw
• adaptor should also expose totally generic helpers - like native fetch or util.request (function) or http.request (operation)

Maybe the generic helper should not be an operation because we're saying "you're on your own buddy"

[josephjclark]

Probably be strict and not allow absolute URLs from adaptor helpers

Then work out how to expose common http. Or just expose the existing legacy functions