Add documentation about different organization discovery options

[SujanSanjula96]

Document issue type

Type/Improvement (Suggest changes to enhance the clarity, usability, or accuracy of existing content)

Description

Currently, we support org name based organization discovery, org id based organization discovery and email domain based organization discovery OOTB. Also, now we have the support for the custom discovery handlers as well. We need to add documentation about the above discovery types. Currently we only have dedicated section for email domain based discovery only/

Version

IS-7.0.0, IS-7.1.0