Docs: Improve filters documentation

[yeikel]

Issue submitter TODO list

• I've searched for an already existing issues here
• I'm running a supported version of the application which is listed here and the feature is not present there

Is your proposal related to a problem?

No

Describe the feature you're interested in

Currently, the documentation for the filters is a bit barebones and simplistic. Users like me that are new to the syntax are not able to take full advantage of this feature.

I would appreciate it the built in documentation of the UI is extended with some sample documents as well as more examples.

Describe alternatives you've considered

Reading the documentation manually is always an option but the UI should try to be self-documented if possible

Version you're running

2956664

Additional context

No response

[siegenthalerroger]

The web documentation (FAQ) should also be updated to match: https://ui.docs.kafbat.io/faq/faq#smart-filters-syntax

[Haarolean]

PRs are welcome for this, our docs are open source as well: https://github.com/kafbat/ui-docs