swarm/api: Remove bzz-resource scheme

[nolash]

bzz-resource is supposed to provide low-level access to raw resource update data. But the http layer isn't really intended for this type of usage.

Low-level operations on resource updates should be kept to direct go integration, optionally through rpc if needed.

[jpeletier]

Hmm, after going through the code, I would keep this API endpoint. It is very useful for the user to create, update and obtain information about resources they want to update, or as of #704, obtain the information to be signed. Can we reconsider this?

[nolash]

it's a keep