Deprecate or remove (EDIT(jcnelson): or fix) the `/v2/fees/transfer` endpoint about stacks-core

[jcnelson]

How about, since people apparently use this endpoint, we instead fix /v2/fees/transfer to do what it's supposed to do?

[diwakergupta]

How about, since people apparently use this endpoint, we instead fix /v2/fees/transfer to do what it's supposed to do?

From being on the receiving end of a lot of questions / tech support requests around this, I'll just say one endpoint is better / less confusing than two.

[jcnelson]

If you're seeing people query this endpoint, then I think it's safe to assume that the questions / tech support requests aren't going to go away if we just disable it. They'll just ask why it broke.

The endpoint is indeed broken insofar as it returns incorrect data. However, it's straightforward to make it return correct data, since it can rely on the same machinery that /v2/fees/transaction uses. Also, it's a lot less clunky than /v2/fees/transaction if you're just sending a token-transfer -- it'll give you a scalar fee in response to a body-less GET request, as opposed to requiring you to serialize and POST your transaction to the node and then parse a JSON response.

I'll go ahead and fix it.

[jcnelson]

Fixed: #4754