add ocagent, elasticsearch, datadog, jaeger exporters

[oker1]

[googlebot]

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[Sebruck]

Thanks a lot for your contribution @oker1 !! ❤️

Could you please sign the google CLA so we can get this merged as soon as possible?

[oker1]

I have to get corp. approval first.

[Sebruck]

Alright, thanks for the information! Please contact me when you need any support.