Automatic merge from submit-queue (batch tested with PRs 59030, 64666, 66251, 66485, 66813). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

A large set of improvements to the Stackdriver components.

**What this PR does / why we need it**:
This PR delivers a large set of improvements for both the Stackdriver Logging agent and the Stackdriver Metadata agent.

**Release note**:
```release-note
Metadata Agent Improvements
Bump metadata agent version to 0.2-0.0.21-1.
Expand the metadata agent's access to all API groups.
Remove metadata agent config maps in favor of command line flags.
Update the metadata agent's liveness probe to a new /healthz handler.

Logging Agent Improvements
Bump logging agent version to 0.2-1.5.33-1-k8s-1.
Appropriately set log severity for k8s_container.
Fix detect exceptions plugin to analyze message field instead of log field.
Fix detect exceptions plugin to analyze streams based on local resource id.
Disable the metadata agent for monitored resource construction in logging.
Disable timestamp adjustment in logs to optimize performance.
Reduce logging agent buffer chunk limit to 512k to optimize performance.
```