Load increase rework

[franksn90]

Content: The change concerns the test generation for load increase RQAs. In essence, the improvements are:

• The load profile no longer determines the duration of the test, but the load profile is fitted to a specified test duration
• The new load profile is more accurate, i.e., it does not set higher request numbers than the specified max amount of requests (which usually happened in the previous implementation in the last stage)
• The number of stages in the load profile can be specified, allowing for more control of the load profile's smoothness

These are changes I implemented at the Hackathon - I hope the Java-2-Kotlin transformation did a good job ;D

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This change is 

[franksn90]

@LitschiW Thank you for the excellent review and the improvements :)