Description of problem:
When deploying the CodeReady Workspaces on ROKS and using the IBM Cloud IAM as a authentication provider, it is impossible to create a workspace because of the username format and special characters being IAM#user@domain.com

Version-Release number of selected component (if applicable): 4.3.z

How reproducible: always

Steps to Reproduce:
1. ROKS
2. Create a namespace & deploy the Red Hat CodeReady Workspaces operator
3. Create an instance using "openShiftoAuth: true"
4. Access CodeReady Workspaces and create a workspace

Actual results:
1. with standard IAM username string iam#rovandep@redhat.com-codeready:
The specified namespace iam#rovandep@redhat.com-codeready is invalid: a DNS-1123 label must consist of lower case alphanumeric characters or '-', and must start and end with an alphanumeric character (e.g. 'my-name', or '123-abc', regex used for validation is '[a-z0-9]([-a-z0-9]*[a-z0-9])?')

2. with modification of IAM username within the Update profile windows at first login to email address here rovandep@redhat.com:
The specified namespace rovandep@redhat.com-codeready is invalid: a DNS-1123 label must consist of lower case alphanumeric characters or '-', and must start and end with an alphanumeric character (e.g. 'my-name', or '123-abc', regex used for validation is '[a-z0-9]([-a-z0-9]*[a-z0-9])?')

3. with modification of IAM username within the Update profile windows at first login to username without @domain.com like rovandep in my case
Working

Expected results:
Options in order of preferences from MHO:
1. update operator documentation about the character limitation to avoid such behavior which will required Admin privileges on keycloack to delete or modify the username
2. support the IBM IAM integration from a CodeReay Workspaces perspective with a routine to propose the username bit of the overall IBM Cloud IAM username
3. introduce RFE for CodeReady Workspaces to support # and @ characters

Additional info: