Add iml-graphql-queries crate

[jgrund]

Add a new crate, iml-graphql-queries that serves as a simple client
query builder.

It has no dependency on transport and can be used in both wasm and
native contexts.

Signed-off-by: Joe Grund jgrund@whamcloud.io

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This change is 

[johnsonw]

Do you think it would be beneficial to have a run command that would make the HTTP call to the graphql endpoint with the specified query?

[jgrund]

Do you think it would be beneficial to have a run command that would make the HTTP call to the graphql endpoint with the specified query?

No, this is purposely client agnostic so it can be used with wasm and native code, i.e. seed on the front-end and reqwest on the backend.

[ip1981]

Might need a helper to decode the responses. Like

serde_json::from_value(resp.get("data").unwrap().get("createSnapshot").unwrap().clone())

[jgrund]

Might need a helper to decode the responses.

Yeah, I'll try to do that in a follow-on

[jgrund]

Went ahead and implemented response support as well:

Here's how I'm creating a request in seed:

snapshot::create::build(&model.fs_name, &model.name, model.comment.as_ref(), Some(model.barrier));

let req = fetch::Request::graphql_query(&query);

orders.perform_cmd(req.fetch_json_data(|x| Msg::SnapshotCreateResp(x)));

and here's how the response looks like in msg:

SnapshotCreateResp(fetch::ResponseDataResult<Response<snapshot::create::Resp>>)

Will probably write a seed helper to collapse the nesting of that response, but that can be in another patch.