Collect OpenTelemetry collector telemetry data for service owners

[mxiamxia]

Is your feature request related to a problem? Please describe.
As the OpenTelemetry collector maintainer and backend service owner, I want to have a way to collect the collector telemetry data so I can

• Get the adoption rate on each version of the released OpenTelemetry Collector that sends metrics/traces/logs data to its backend services
• Identify the running environment where OpenTelemetry collector is running. (Eg, for AWS customers, we want to tell where the collector is running. Eg, ECS, EKS, Lambda, etc.)
• Identify the customers who got impacted by the urgent issues(security, sever bugs, etc) that detected on a specific OpenTelemetry Collector version. So the service owner should be able to notify those customers. We can find the impacted customers by querying the customer IDs in service logs sent from OpenTelemetry Collector.

Describe the solution you'd like
When OpenTelemetry Collector sends traces/metrics/logs data to backend in the exporters, we can attach the telemetry data into User-Agent of the API requests in the exporters.
For example,
Set UserAgent to: OpenTelemetryCollector v0.1.0 go1.14 linux amd64 ECS

Implementation,
Create a common module under internal folder to construct the telemetry data content for all the exporters to use before sending the data to backend services.

[mxiamxia]

Added user agent in X-Ray exporter. open-telemetry/opentelemetry-collector-contrib#1730

[robbkidd]

Is this an enhancement that could be contributed sooner rather than later? Troubleshooting data issues from a multitude of environments not under our control is complicated by the absence of any information received about Collectors in the transmission hand-offs. It's particularly painful to troubleshoot data issues during this period of transition from older OTel proto versions to v0.9.0 as the combinations of various SDK implementations and various Collector versions running update.