String based attributes for style comparison filter & configurable number of color map categories

[FilipLeitner]

Description

• String based attributes for style comaprison filter along with some unit tests
• Configurable number of color map categories
• Fixes bug where styler rule removal created new instance of rule thus disconnecting stylerService.styleObject used to produce SLD from styler UI

Related issues or pull requests

closes #5152 closes #4886

Pull request type

• [x] Bugfix
• [x] Feature
• [ ] Dependency updates
• [ ] Code style update (formatting, renaming)
• [ ] Refactoring (no functional changes, no api changes)
• [ ] Build related changes
• [ ] Documentation content changes
• [ ] Other (please describe)
• [ ] I am unsure (we'll look into it together)

Do you introduce a breaking change?

• [ ] Yes
• [x] No
• [ ] I am unsure (no worries, we'll find out)

Checklist

• [x] I understand and agree that the changes in this PR will be licensed under the [MIT License]
• [ ] I have followed the guidelines for contributing
• [ ] The proposed change fits to the content of the code of conduct
• [ ] I have added or updated tests and documentation, and the test suite passes (run npm test locally)
• [ ] I'm lost; why do I have to check so many boxes? Please help!