Use UDS for optimistic block and bundle streams in the Auctioneer

[itamarreif]

We want to minimize transport issues and latency. Since we assume the optimistic block and bundle streams (link to proto) will be served by a sequencer in the same cluster as the auctioneer we can use UDS instead of TCP for the gRPC connection.

• tonic/examples/src/uds

┆Issue Number: ENG-979

[joroshiba]

This issue is stale because it has been open 45 days with no activity. Remove stale label or this issue
be closed in 7 days.

[joroshiba]

This issue was closed because it was stale

[SuperFluffy]

We still want this at some point.