Query pinned wasm codes

[alpe]

It is currently not possible to query pinned codes or check if a wasm code id is pinned.
CLI support would be nice.

[ethanfrey]

Yes, this would be a good query (return list of code ids). Both via grpc and via cli.

[alpe]

As @ethanfrey has pointed out in #633 (review) the implementation does not include the "pinned" data in the code info.

My original thinking was that we need any way to query if a contract is pinned and not necessarily both ways. Getting the list of all pinned contracts was more beneficial to me than by contract id. For my case I would consider this task done and but encourage anybody who really needs this info by code id to open a new task.

[ethanfrey]

Maybe we can make a 1.x /2.0 query issue for this.

It is not essential, but would be nice to have