Experiment with fs2-grpc aspect middleware

[iRevive]

typelevel/fs2-grpc#669

Seems to be working fine:

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Here is the OpenTelemetry spec: https://opentelemetry.io/docs/specs/semconv/rpc/rpc-spans/#rpc-client-span

Name	Type	Description	Requirement Level
rpc.system	string	A string identifying the remoting system. Well-known identifiers: grpc, java_rmi, dotnet_wcf.	Required (Development)
rpc.method	string	The name of the (logical) method being called, must equal the $method part in the span name.	Recommended (Development)
rpc.service	string	The full (logical) name of the service being called, including its package name if applicable.	Recommended (Development)
server.address	string	RPC server host name.	Required (Stable)
server.port	int	Server port number.	Conditionally Required (Stable)
network.peer.address	string	Peer address of the network connection - IP address or Unix domain socket name.	Recommended (Stable)
network.peer.port	int	Peer port number of the network connection.	Recommended if network.peer.address is set (Stable)
network.transport	string	OSI transport layer or inter-process communication method.	Recommended (Stable)
network.type	string	OSI network layer or non-OSI equivalent.	Recommended (Stable)

Right now, we can provide rpc.system, rpc.method, and rpc.service.
server.* and network.* attributes can likely be provided as static attributes when creating a middleware.