feat: allowing subscribe to new blocks with namespace

[moldis]

Closes #2737

This PR allows to subscribe to blob by multiple namespaces.

• Added new function Subscribe, which contains list of Namespaces.
• Added unit-tests to test function above.
• Updated RPC methods with function above.

[distractedm1nd]

Thank you for taking this on!

I don't think blob Subscribe should return a map of height -> map of namespace -> blob list. This would mean sending all the blobs for all previous heights every block.

I think it would make more sense to return something like a

type BlobsubResponse struct {
          height uint64
          blobsByNamespace BlobsByNamespace
}


Subscribe func(context.Context, []share.Namespace) (<-chan BlobsubResponse, error) `perm:"read"`

I don't like the blobsubresponse name yet but the structure should probably be the same. Thoughts @renaynay, @walldiss ?

[moldis]

Thank you for taking this on!

I don't think blob Subscribe should return a map of height -> map of namespace -> blob list. This would mean sending all the blobs for all previous heights every block.

I think it would make more sense to return something like a

type BlobsubResponse struct {
          height uint64
          blobsByNamespace BlobsByNamespace
}


Subscribe func(context.Context, []share.Namespace) (<-chan BlobsubResponse, error) `perm:"read"`

I don't like the blobsubresponse name yet but the structure should probably be the same. Thoughts @renaynay, @walldiss ?

Thanks, good idea. Now looks too overloaded with map, will change it to this structure

[distractedm1nd]

Closing in favor of #3539