WHAT
based of MGDAPI-4963 create a sop to allow sre to configure a customdomain/wildcard domain in 3scale

Custom Domains should be supported in RHOAM in the following way:

Prior to installation of RHOAM/3scale a customer should be able to specify the custom domain in the add on parameter field.

After the installation of RHOAM/3scale a customer can request a change to the custom domain via a support ticket. SRE can follow an SOP to change the wildcard domain for 3scale which should facilitate the changing of the admin, developer and master portals.

New tenants, developer and admin portals, should have the new wildcard domain on creation. 

HOW
Change rhoam's logic if necessary to enable the ability to set the wildcard domain in 3scale
you can either disable the blocking logic in the bootstrapReconciller.go
or adjust how rhoam handles the wild card domain in apimanager https://github.com/integr8ly/integreatly-operator/blob/master/pkg/products/threescale/reconciler.go#L727

TESTS

After the creation of the SOP verify it against an install of RHOAM with a custom domain (addon param) and without a custom domain

Verify that changing the addon param has no affect, and this should be clear from the documentation and addon param description

SRE have requested the SOP to cover rollback. Verify that the SOP can revert to the default cluster domain for 3scale. 

After updating the wildcard domain, following the SOP, verify that new tenants use the new domain, both admin and developer portals. 

DONE

2 things we are trying to achieve:

1. The RHOAM Operator should not support modifying the wildcard domain after 3scale is installed.
2. SRE should have an SOP to modify the wildcard domain after a 3scale install. 

Create an RFE on ThreeScale project to support this (this may exist, link here)