Validation was added on the config entry kind since that is called when
validating config entries to bootstrap via agent configuration and when
applying entries via the config RPC endpoint.
The api module has decoding functions that rely on 'kind' being present
of payloads. This is so that we can decode into the appropriate api type
for the config entry.
This commit ensures that a static kind is marshalled in responses from
Consul's api endpoints so that the api module can decode them.
Existing config entries prefixed by service- are specific to individual
services. Since this config entry applies to partitions it is being
renamed.
Additionally, the Partition label was changed to Name because using
Partition at the top-level and in the enterprise meta was leading to the
enterprise meta partition being dropped by msgpack.
