[WIP] Tracing

[refs]

This branch creates a root trace, sends it over the wire for every other service to add spans.

Start the service with tracing enable:

go run cmd/ocis-proxy/main.go \
--config-file ./config/.proxy-example.json server \
--tracing-enabled \
--tracing-type jaeger \
--tracing-collector http://localhost:14268/api/traces

Start ocis-konnectd as explained here: owncloud/ocis-konnectd#47

go to https://localhost:9200/signin/v1/identifier
go to http://localhost:16686/
select the proxy service from the service dropdown
click on find traces

That set of steps should end in something like this:

and by clicking on a trace, more details are displayed:

[update-docs]

Thanks for opening this pull request! The maintainers of this repository would appreciate it if you would create a changelog item based on your changes.

[IljaN]

LGTM

[micbar]

@refs needs a rebase

[ownclouders]

Here is an overview of what got changed by this pull request:

Complexity increasing per file
==============================
- pkg/command/server.go  1
         

See the complete overview on Codacy

[butonic]

@refs can you rebase? we want to add jaeger to the docker compose. the proxy should show up ...

[refs]

rebasing was a headache. Redoing the branch was easier. Closing in favor of #64