Document Elastic OpenTelemetry Collector Exporter

[bmorelli25]

Add documentation for the Elastic OpenTelemetry Collector Exporter.

I like the format some of the other exporters have used: Add basic exporter config values and a sample config in the opentelemetry-collector-contrib repo's readme.md file. We can then link out to our own docs where we'll document the feature in its entirety.

Thoughts? Other ideas?

cc @axw

Related Issues

• Feature: OpenTelemetry exporter #98

[axw]

@bmorelli25 I copied the approach taken by other contrib exporters:

https://github.com/axw/opentelemetry-collector-contrib/blob/elasticexporter/exporter/elasticexporter/README.md

Linking to a page in our docs sounds good.

[cyrille-leclerc]

@axw , @bmorelli25 I see that Splunk is adding a Slunk HEC sample to the otel collector code repository: open-telemetry/opentelemetry-collector-contrib#266 .
This could be an interesting idea