Feature/multiple heuristics

[ellmau]

What does this PR do?

To allow multiple heuristics, a generic approach has been implemented.

Checklist before creating a non-draft PR

• All tests are passing
• Clippy has no complains
• Code is rustfmt formatted
• Applicable labels are chosen (Note: it is not necessary to replicate the labels from the related issues)
• There are no other open Pull Requests for the same update/change.
  • If there is a good reason to have another PR for the same update/change, it is well justified.

Checklist on Guidelines and Conventions

• Commit messages follow our guidelines
• Code is self-reviewed
• Naming conventions are met
• New features are tested
  • quickcheck has been considered
  • All variants are considered and checked
• Clippy Compiler-exceptions
  • Used in a sparse manner
  • If used, a separate comment describes and justifies its use
• rustdoc comments are self-reviewed and descriptive
• Error handling
  • Use of panic!(...) applications is justified on non-recoverable situations
  • expect(...) is used over unwrap() (except obvious test-cases)
• No unsafe code (exceptions need to be discussed specifically)