Torii grpc entities query

[broody]

This PR exposes a RetrieveEntities grpc api, only implemented querying by keys clause, querying by attribute and composite clause to be implemented.

Also, map_row_to_ty method is not currently used, will eventually be used by graphql

Query format is similar to graphql, supply keys array and it will return all entities matching those keys. For wildcard, leave key part blank. Only pagination supported is limit offset.

{
    "query": {
        "clause": {
            "keys": {
                "keys": [
                    [], <-- wildcard
                    [3]
                ]
            }
        },
        "limit": 2,
        "offset": 0
    }
}

Return format

{
    "entities": [
        {
            "models": [
                {
                    "members": [
                        {
                            "name": "record_id",
                            "value": {
                                "uint_value": "2"
                            }
                        },
                        {
                            "name": "subrecord_id",
                            "value": {
                                "uint_value": "3"
                            }
                        },
                        {
                            "name": "type_u8",
                            "value": {
                                "uint_value": "0"
                            }
                        },
                        {
                            "name": "random_u8",
                            "value": {
                                "uint_value": "69"
                            }
                        }
                    ],
                    "name": "Subrecord"
                }
            ],
            "key": "AMtAZ2/a/AeZjxORv2Y1a18MltXmG79efsCqAyDdj5s=" <-- this is bytes
        }
    ]
}

[tarrencev]

I think we will eventually need a way to invalidate a cache entry when we index an update to an existing model. Lets create an issue to track it

[tarrencev]

I think it is fine to return an error in this case. 64 joins is a reasonable limit

[tarrencev]

Let's also rename this to MemberClause in a future PR