Update stackdriver plugins to reflect new product naming

[danielnelson]

Required for all PRs:

• Signed CLA.
• Associated README.md updated.
• Has appropriate unit tests.

[reimda]

Do we need to rename the plugins and directories too? It looks like they've almost completely rebranded to Google Cloud Monitoring.

It looks like the agent binaries are still named stackdriver so maybe it's not a big deal to leave that brand in telegraf?
https://cloud.google.com/monitoring/agent/install-agent

[reimda]

Heading should be "Google Cloud Monitoring Input Plugin"

[reimda]

Heading should be "Google Cloud Monitoring Output Plugin"

[danielnelson]

It's possible we will want to add a plugin alias in the future, similar to with http_listener/influxdb_listener. We could name it cloud_monitoring to match cloud_pubsub. For now though, I think we should leave it primarily as stackdriver since I think this is the name with the most recognition.

[danielnelson]

Updated the plugin readme titles to, for example, Stackdriver Google Cloud Monitoring Input Plugin.

[uday1984]

"Google Cloud Monitoring Input Plugin"
Can you share the definition to be define on the telegraf.conf file for the metric label and resource label
I defined the conf file as below and verifed the data is appearing in GoogleCloudPlafform. However telegraf is not able to read it.

filter: "metric.type = "compute.googleapis.com/instance/cpu/usage_time"" AND "metric.labels.instance_name = "demo-instance-1""

ERROR

2021-09-17T12:43:11Z E! [inputs.stackdriver] Failed iterating time series responses: "name:"projects/cfs-practice" filter:"metric.type = \"compute.googleapis.com/quota/subnet_ranges_per_vpc_network/exceeded\" AND resource.labels. = \"\" AND metric.labels. = \"\"" interval:{end_time:{seconds:1631882284} start_time:{seconds:1631882224}}": rpc error: code = InvalidArgument desc = Field filter had an invalid value of "metric.type = "compute.googleapis.com/quota/subnet_ranges_per_vpc_network/exceeded" AND resource.labels. = "" AND metric.labels. = """: Could not parse filter "metric.type = "compute.googleapis.com/quota/subnet_ranges_per_vpc_network/exceeded" AND resource.labels. = "" AND metric.labels. = """; syntax error at line 1, column 104, token ' ';