Binding params in HTTP queries

[MarinPostma]

It would be interesting to be able to bind parameters in HTTP queries, once #12 lands. I'm not completely sure about the API though.

Currently, there request payload looks like this:

{
    "statements": [/* stmts */],
}

We could for, for example add a params fields to the payload, with variables scoping all the statements in statement, e.g:

{
    "statements": ["select * from users where name = $name"],
    "params": {
        "name": "adhoc",
    }
}

another option could be statement-scoped variables, like so:

{
    "statements": [{ "statement": "select * from users where name = $name", "params": {"name": "adhoc"}}],
}

[CodingDoug]

This issue seems closeable @MarinPostma.