The cluster name length limit is being increased to 54 characters for both OSD and ROSA.

To support longer cluster names, CS now has a separate domain_prefix field with a maximum of 15 characters. This field will be populated for all existing clusters and is also set when users create new clusters without specifying the domain_prefix. In this case it is the first 15 characters of the UUID, tweaked if necessary to avoid collisions.

The increased cluster name length needs to be supported during cluster creation, and the domain prefix should be visible for day-2 information purposes.

Acceptance Criteria

• Length limit for the cluster name field is increased to 54 for all wizards
• An optional Domain prefix field is added. This field should have the same validations as the current cluster name field (with 15 character length limit) but for uniqueness the query should check for other clusters with the same domain_prefix. This field is only shown when the Customize domain prefix checkbox is selected, as per the design from https://issues.redhat.com/browse/OCMUX-58 (see also https://redhat-internal.slack.com/archives/C06JPKPJYJD/p1709155705968139)
• Helper text needs to be updated for at least Cluster name and possibly Domain prefix as well
• Domain prefix is shown on the cluster details page for all clusters with a CS record.
• All code is guarded by feature flag longer-cluster-name-ui