fixes #5028 - changing organization_id label to ID

To date, `organization_id` in HTTP params and in the urls sent to Katello have actually been the `label` of the organization. This problem has been discussed before with folks agreeing, "Eh, it works," and moving on.  This problem again resurfaced when writing the apidoc for Katello's API. params everywhere were defined as `:organization_id` when they were, in fact, still the `label`. Propagating down the wire to Hammer CLI's options, anything that needed a specific organization asked for `--organization-id` when it's actually looking for the label, but then displayed the organization's label as `label` and the ID as `ID`. This is quite confusing for people trying to use Hammer.

This change switches looking up by an organization's `label` to looking up by the `ID`. Urls will no longer be `/katello/api/v2/organizations/ACME_Corporation/ ...` but will now appear as `/katello/api/v2/organizations/1/ ...`. Likewise, any `organization_id`  in HTTP params should be that organization's database `ID` instead of its `label`.