feat: add nested entity filters

[Sekhmet]

Depends on #246

This PR adds support for filtering entities by their subentities, for example following query becomes now possible:

{
  spaces (where: { metadata_: { name_contains: "Shadow DAO"}}) {
    id
    metadata {
      id
      name
      executors
      executors_types
    }
    voting_delay
  }
}

Test plan

Test against snapshot-labs/sx-api#181

[Sekhmet]

Normalized filter name to match TheGraph.

[bonustrack]

Awesome, this is a great feature. I tried and it seem to work well, I have just these 2 issues:

When I try to query the sub field "id" it will fail with this error:

I've tested on TheGraph a similar query and it works (they keep "id" filter in the sub entity "where").

Also when I try to query a sub entity using a required field as filter it fail. Here is my schema:

...
type User {
  id: String!
  name: String
  about: Text
  discussion_count: Int! # required field
  vote_count: Int! # required field
}
...

Here is the query and response I get:

Without this feature I imagine we wouldn't be able to do things like search on proposals on SX-UI, now I understand why you were looking on adding metadata directly in the Space entity level. It's great that you take that different approach, it will make it easier to integrate on UI as we can keep same format with the subgraph APIs.

[bonustrack]

tACK