Remove SSL Pinning (APPS-1821)

[cmaier]

We don't do SSL Pinning anymore. Anywhere.
Due to this, the SSL Pinning has been removed and SSL Pinning for the payment provider Datatrans has been deactivated.

APPS-1821

How to test?

• Integrate this branch in any of our projects and see if requests still work.
• Check in a project w/ Datatrans as payment provider if checkouts are proceeded as usual.

Definition of Done

• Issue is linked
• All requirements of the issue are fulfilled
• Changelog is updated
• Documentation is updated
• Self-Review
• Review with the Product Owner (Release-Variante o. Minified Build)

App Tests

• Minified build has been tested (aka. Release Build)
• Environments have been taken care of (Production/Staging)
• Supported languages have been tested
• Light-/Dark-Mode has been tested
• Edge-Cases have been tested
• Android API Levels have been taken care of (minSdk?)

Testing

• Tests have been written (aka Unit-Tests, Integration-Tests, ...)