Move namespace from query param to path part

Per the accepted namespaces design, this PR modifies the URL patterns as follows:

| Action | HTTP Verb | Path | Description |
| ---- | ---- | ---- | ---- |
| CREATE | POST | /api/{version}/ns/{ns}/{resourceType}/ | Create instance of {resourceType} in namespace {ns} |
| GET | GET | /api/{version}/ns/{ns}/{resourceType}/{name} | Get instance of {resourceType} in namespace {ns} with {name} |
| UPDATE | PUT | /api/{version}/ns/{ns}/{resourceType}/{name} | Update instance of {resourceType} in namespace {ns} with {name} |
| DELETE | DELETE | /api/{version}/ns/{ns}/{resourceType}/{name} | Delete instance of {resourceType} in namespace {ns} with {name} |
| LIST | GET | /api/{version}/ns/{ns}/{resourceType} | List instances of {resourceType} in namespace {ns} |
| WATCH | GET | /api/{version}/watch/ns/{ns}/{resourceType} | Watch for changes to a {resourceType} in namespace {ns} |

The typical actor for the following requests are the k8s service or k8s admin as enforced by k8s Policy.

| Action | HTTP Verb | Path | Description |
| ---- | ---- | ---- | ---- |
| WATCH | GET | /api/{version}/watch/{resourceType} | Watch for changes to a {resourceType} across all namespaces |
| LIST | GET | /api/{version}/list/{resourceType} | List instances of {resourceType} across all namespaces |

The legacy API patterns for k8s are an alias to interacting with the *default* namespace as follows.

| Action | HTTP Verb | Path | Description |
| ---- | ---- | ---- | ---- |
| CREATE | POST | /api/{version}/{resourceType}/ | Create instance of {resourceType} in namespace *default* |
| GET | GET | /api/{version}/{resourceType}/{name} | Get instance of {resourceType} in namespace *default* |
| UPDATE | PUT | /api/{version}/{resourceType}/{name} | Update instance of {resourceType} in namespace *default* |
| DELETE | DELETE | /api/{version}/{resourceType}/{name} | Delete instance of {resourceType} in namespace *default* |

Suggestion: I think it'd be clearer if you took these paths and put them directly in the table above (doubling the size of the table). That'd make it easier to test the "all" namespace, which seems to be untested.