Activity source split for User/Runtime grain calls

[rwkarg]

This allows for selectively choosing activity for runtime grains (like IMembershipTable, IRemoteGrainDirectory, or IDeploymentLoadPublisher) or only user created grains (what the user has created for their system/application).

It is assumed that consumers will primarily want the user grain Activity and not also the runtime/internal grain calls.

Mechanically, this is achieved by looking to see if the namespace of the grain starts with "Orleans". There is the possibility that a user can create their own grain in a namespace starting with "Orleans" (ex. Orleans.MyCompany.MyApp) but this is not an idiomatic pattern for namespace naming so it may be sufficient to document this behavior.

This does introduce a breaking change for current consumers of ActivitySources.
For example, users using OpenTelemetry (and similarly for directly listening with an ActivityListener) currently add the "Microsoft.Orleans" source and get all runtime and user grain Activity.

This PR would require those users to do one of the following in their code:

• Make no changes and stop getting any Orleans related Activity
• Add the source as "Microsoft.Orleans.*" instead (note the asterisk/wildcard added) to get the existing set of both user and runtime grain Activity
• Add the source as "Microsoft.Orleans.User" to get only the user grain Activity
• Add the source as "Microsoft.Orleans.Runtime" to get only the runtime grain Activity

Microsoft Reviewers: Open in CodeFlow

[dnfadmin]

All CLA requirements met.

[ReubenBond]

LGTM. This will incur some reflection overhead to get the target's namespace, but perhaps that is acceptable. An alternative might be for us to guarantee a prefix for all internal grains, such as "sys." or "ms."