Write missing E2E test for Git URL rewrite feature

[HeavyWombat]

The Git URL rewrite feature is only covered by unit tests. However, the build controller is using the Git step and can set the flag for enabling Git URL rewriting so this needs to be tested in an E2E test as well.

The setup is as follows:

• Controller logic for Git URL rewrite is disabled by default through an environment variable.
• In case it is set to "true", the controller will add an additional flag to the Git wrapper binary.
• This will trigger additional code to be executed in the Git wrapper.

Idea: Use the HTTPS URL used in the unit test and build an E2E test around it with: Git URL rewrite enabled, HTTPS URL used as a source pointing to a private repository and a private key being specified.