[Access] Enable grpc compression

[peterargue]

grpc supports asymmetric (one sided) compression. Add support for:

• compressing requests to ENs
• compressing responses from ENs
• compressing responses from ANs

along with handing decompression on the server side.

Make compressing requests/responses configurable via a cli flag on ANs/ENs

[Guitarheroua]

Which compressor or compressors should be used for this task, as this is not mentioned directly in the issue? Are there any existing ones that you would recommend, or should new compressors be suggested?

[peterargue]

I'm not sure. Can you do some research and provide suggestions? The communication between EN/ANs are both using go so we can pretty much use anything that we want. The connection between ANs and clients would need to pick more common/accessible options. Ideally we'd use the same in all cases unless there's a compelling reason.