Add Jaeger exporter

[mauriciovasquezbernal]

No too much to add.

Opening the issue to avoid duplicated work, please assign it to me.

[Oberon00]

CC @carlosalberto

[Oberon00]

Please be aware that since we pledged to have a Jaeger exporter for the alpha (see README) it would be great if this was finished this week 😅

[c24t]

We talked with @SergeyKanzhelev a bit about this offline and agreed that the zipkin exporter should work for the alpha instead. The goal is to have some non-trivial exporter, doesn't necessarily have to be jaeger.

That said, we do need a jaeger exporter, and the sooner the better!