[Story] Update EDC documentation for multi-profile support

[ReneSchroederLJ]

As a PURIS user ,
I want improved documentation ,
so that I can understand how to use the EDC integration with the correct EDC version .

Hints / Details

• update the documentation to explain how multi profile support works
• include documentation on how to configure the local deployment for testing older EDC versions
• documentation to be changed includes Admin guide, Arc42 as well as developer documentation in local

Outcome / Acceptance Criteria

Outcome

• the documentation clearly describes how the EDC is used in the application

Acceptance Criteria

• instructions on how to test different versions of the EDC locally are included
• multi-profile support is documented in a clear and concise manner

Out of Scope

• updates to the migration guide should be done as part of the migration concept