Add Authorization Prerequisite

[PDT42]

Added required authorization to prerequisites.

[cla-assistant]

All committers have signed the CLA.

[IvelinaKiryakova]

Thank you for your feedback.
The required authorization "Manage Identity Provisioning" gives the tenant administrator permission to enable the Identity Provisioning within the SAP Cloud Identity Services admin console. It is related to the tenant and what services are enabled there and not so much (or indirectly) to the connectors provided by Identity Provisioning. That is why we've decided to keep the permission description in the initial setup of the tenant and focus on the authentication and communication prerequisites for the connectors.
Thanks you and best regards,
Ivelina