Include grpcurl in Provider Image

[chainzero]

Feature request:

Include the insall of grpcurl in provider image to allow testing within the inventory operator and automation of pod restarts when conditions warrant.

Example use case:

Liveness probe for the inventory operator would restart pod when GPU allocated is greater than capacity/allocatable.

[neyy91]

@chainzero Opened a PR for this: akash-network/provider#405

It installs grpcurl in the provider image so the inventory operator's gRPC API can be probed from inside the container (e.g. the liveness-probe use case described here). grpcurl isn't in apt, so it pulls a pinned, sha256-verified release (v1.9.3) for both amd64 and arm64.