APIs (like /instances) are inconsistently structured or hard to use

Many APIs do not have consistent or easy to use resource structures. For example, `GET /instances/{instanceName}` may return data like
```
{
"instanceName": "Broker_mybrokerhostname_8099",
"hostName": "Broker_mybrokerhostname",
"enabled": false,
"port": "8099",
"tags": [
"DefaultTenant_BROKER"
],
"pools": null
}
```

Meanwhile `PUT /instances/{instanceName}` requires `host` (not `hostname`) and a `type` field (`BROKER`, `SERVER`, `CONTROLLER`).

Mismatched resources like this make the APIs complex to work with and even harder to use by hand.

Additionally, APIs like `PUT /instances/{instanceName}/updateTags` would be great ot use for upserting empty tags, but that does not appear possible since the Swagger UI reports `tags` is required.

Start by comparing the GET and PUT /instances/{instanceName} payloads and the PUT /instances/{instanceName}/updateTags schema in the Swagger UI. Trace where these API contracts are defined, then align the resource fields and determine how empty tags should be accepted; done means the documented request and response structures are consistent and usable.

Written by the indexing model from the issue text.