[v2] Retry failed updates with exponential backoff

[blampe]

Currently, if our automation APIs call fail they return non-nil errors to the operator. In #676 I modified Update to translate these errors into a "failed" status on the Update/Stack, but other operations (preview etc.) still surface these errors and automatically re-queue.

We'd like to retry these failed updates much less aggressively than we retry transient network errors, for example. To accomplish this we do a few things:

• We consolidate the update controller's streaming logic for consistent error handling across all operations.
• We return errors with known gRPC status codes as-is, but unknown status codes are translated into failed results for all operations.
• We start tracking the number of times a stack has attempted an update. This is used to determine how much exponential backoff to apply.
• A failed update is considered synced for a cooldown period before we retry it. The cooldown period starts at 5 minutes and doubles for every failed attempt, eventually maxing out at 24 hours.

Fixes #677

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 78.17259% with 43 lines in your changes missing coverage. Please review.

Project coverage is 53.68%. Comparing base (83f8438) to head (f15ea11). Report is 1 commits behind head on v2.

Files with missing lines	Patch %	Lines
...ator/internal/controller/auto/update_controller.go	71.11%	36 Missing and 3 partials :warning:
...tor/internal/controller/pulumi/stack_controller.go	93.22%	3 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## v2 #709 +/- ## ========================================== + Coverage 50.22% 53.68% +3.46% ========================================== Files 27 27 Lines 2919 2902 -17 ========================================== + Hits 1466 1558 +92 + Misses 1272 1164 -108 + Partials 181 180 -1 ```

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.