Without a `LocalServicePort`, Connect services will try to use the
mapped port even when delivering traffic locally. A user can override
this behavior by pinning the port value in the `service` stanza but
this prevents us from using the Consul service name to reach the
service.
This commits configures the Consul proxy with its `LocalServicePort`
and `LocalServiceAddress` fields.
* adds meta object to service in job spec, sends it to consul
* adds tests for service meta
* fix tests
* adds docs
* better hashing for service meta, use helper for copying meta when registering service
* tried to be DRY, but looks like it would be more work to use the
helper function
* jobspec: breakup parse.go into smaller files
* add sidecar_task parsing to jobspec and api
* jobspec: combine service parsing logic for task and group service stanzas
* api: use slice of ConsulUpstream values instead of pointers
