feat: adds tags and annotations.

[jcchavezs]

Questions to be addressed:

1. name of the file (maybe tags-and-annotations.md?)

Related:

• https://github.com/openzipkin/openzipkin.github.io/issues/22

[codefromthecrypt]

Thanks for owning this! These are seeded from zipkin-api thrift?

You can also compare against the following:

https://github.com/openzipkin/brave/blob/master/brave/src/main/java/brave/Tags.java https://github.com/openzipkin/brave/blob/master/instrumentation/rpc/src/main/java/brave/rpc/RpcTags.java https://github.com/openzipkin/brave/blob/master/instrumentation/http/src/main/java/brave/http/HttpTags.java

https://github.com/openzipkin/brave/blob/94fe807e03160d779a0e98590b5f96fd824aa81a/brave/RATIONALE.md#why-we-dont-tag-errorfalse https://github.com/openzipkin/brave/tree/master/instrumentation/http#span-data-policy https://github.com/openzipkin/brave/tree/master/instrumentation/rpc#span-data-policy

possibly import rationale from here: https://github.com/openzipkin/brave/blob/master/instrumentation/rpc/RATIONALE.md#why-use-rpcmethod-and-rpcservice https://github.com/openzipkin/brave/blob/master/instrumentation/rpc/RATIONALE.md#the-rpcerror_code-tag

possibly in a different PR the pending messaging tags.. https://github.com/openzipkin/openzipkin.github.io/wiki/Messaging-instrumentation-abstraction https://github.com/openzipkin/brave/blob/master/instrumentation/messaging/src/main/java/brave/messaging/MessagingRequest.java#L27-L69 https://github.com/openzipkin/brave/blob/master/instrumentation/messaging/RATIONALE.md#message-id

as later we can delete these references for a link to here

cc @jeqo @mrajah-twttr