Implement Rate Limiting Observations and Throttling

[Habikki]

The current Exception is thrown when Amazon Rate Limits requests:

---> (Inner Exception #445) System.AggregateException: One or more errors occurred. (Rate exceeded)
 ---> Amazon.CodeArtifact.Model.ThrottlingException: Rate exceeded
 ---> Amazon.Runtime.Internal.HttpErrorResponseException: Exception of type 'Amazon.Runtime.Internal.HttpErrorResponseException' was thrown.

Observationally, this only occurred when the process was run off AWS Infra lending to the idea that rate limits are different on-network, or simply that the external system was more performant.

At present no observation is given to rate limiting which should be implemented, but acting on the rate limiting will require rethinking of how discovery and removal occur.

As discovery and removal are already separated, the changes here reside within ProcessRemovalsAsync(). The process queue should be processed within bounds of a TPS rate limit respecting an exponential backoff delay if a ThrottlingException is encountered.

[Habikki]

Offending line occurred earlier than thought, in the discovery phase:

https://github.com/NeoAgi/NeoAgi.AWS.CodeArtifact.Pruner/blob/main/NeoAgi.AWS.CodeArtifact.Pruner/Worker.cs#L202

[Habikki]

Current implementation of limiting TPS can be thought of as:

1. Fill up a work action queue (No Limit)
2. A process counter ticks every second resetting a TPS counter.
3. When the TPS is below a set threshold, the work scheduler assigns queued items to worker threads (Statically set to 20)

While this limits calls to a known TPS, in practice it does so by executing calls in batches of the TPS window if the calls are rapid like CloudArtifact Calls are. Some level of smoothing should be applied. Proposed changes:

• [x] Stagger the Read Queue after a backoff has been reached. Conceptually divide a second by the TPS, delaying the schedule by each for the second after full TPS is reached (Added in e18c0f6d5150548e48da1b066dba2dc86a72b6ac).
• [x] To limit the work queue, bring the initial discovery process into the work queue (added in 3fdc85b).
• [x] Properly Catch ThrottlingExceptions and replay the action, inforcing a sustancial delay (5 - 10 seconds) to avoid an exponential backoff. (mostly implemented in 8b57079)
• [x] Add configuration parameters to accept TPS Limits (added in 784223d)