Automate more of the Kubernetes hosting experience

[ReubenBond]

This PR simplifies the procedure of using the Microsoft.Orleans.Hosting.Kubernetes package by automating more of the process. With this PR, users will no longer need to specify labels or environment variables in their pod specs.

It manages this by:

• Inferring pod name from Environment.MachineName if not configured via env vars
• Inferring pod namespace from /var/run/secrets/kubernetes.io/serviceaccount/namespace if not configured via env vars
• Updating labels on the pod spec during startup to match the internally configured (eg, default) ServiceId & ClusterId if they are not configured via labels
• Selecting the most appropriate PodIp based on the IANA private IPv4 address ranges if not configured via env vars

Additionally, it filters out non-Active members when performing the on-start purge of unmatched silos. This prevents a race that exists today.

It adds retries to initialization and demotes the Error-level log when Kubernetes drops a watch to Debug (it's not actionable, is common/normal, and is retried indefinitely)

Patching the pod resource (to update labels for discovery) requires the patch verb on the pod's role binding. The package will spit out a log line with an example binding if it receives a permissions error trying to list/get/patch pods

Microsoft Reviewers: Open in CodeFlow