* Replace Helm Hub with Artifact Hub
Signed-off-by: Scott Rigby <scott@r6by.com>

* Update link to new doc entry for Monocular compatible search API
Signed-off-by: Scott Rigby <scott@r6by.com>

* Add struct for Artifact Hub data, and return correct URL for both artifact hub instances and backwards compatibility for Monocular search API
Signed-off-by: Scott Rigby <scott@r6by.com>

* Keep default endpoint hub.helm.sh, so the helm org controls the domain. At least until artifacthub moves to CNCF incubation
Signed-off-by: Scott Rigby <scott@r6by.com>