Histogram metric fixes for container insights

[chadpatel]

Description:

1. some metrics were incorrectly regex'd as histograms, they were not being emitted because the regex was wrong
2. some container insights metrics are sourced as prometheus histograms, these were not getting converted to deltas, resulting in useless metrics
3. fix linter errors in unrelated files

example of metrics that are actually gauge and not histogram:

# HELP apiserver_storage_size_bytes [ALPHA] Size of the storage database file physically allocated in bytes.
# TYPE apiserver_storage_size_bytes gauge
apiserver_storage_size_bytes{cluster="etcd-0"} 1.0092544e+07

apiserver_storage_db_total_size_in_bytes{endpoint="http://10.0.160.16:2379"} 1.0092544e+07
apiserver_storage_db_total_size_in_bytes{endpoint="http://10.0.32.16:2379"} 1.0080256e+07
apiserver_storage_db_total_size_in_bytes{endpoint="http://10.0.96.16:2379"} 1.0084352e+07

I don't have etcd_db_total_size_in_bytes in my cluster because it has been replaced with apiserver_storage_db_total_size_in_bytes

Link to tracking Issue:

Testing: end to end

gauge fixes:

delta histograms:

Documentation:

[chadpatel]

I removed these comments because I don't think it is accurate to say that it is a "bug" that we need to change the behavior on. Changing the behavior here is a breaking change for customers. To implement the "issue" we would need to make this configurable or onboard highly specific use-cases (like the one in this PR)