freeze (make sticky) header row in tabular files

[hujambo-dunia]

Linked to issue #17380

Table header rows always visible during scrolling

How to test the changes?

(Select all options that apply)

• I've included appropriate automated tests.
• This is a refactoring of components with existing test coverage.
• Instructions for manual testing are as follows:
  1. [add testing steps and prerequisites here if you didn't write automated tests covering all your changes]

License

• I agree to license these and all my past contributions to the core galaxy codebase under the MIT license.

[simonbray]

Thanks for working on this @hujambo-dunia, very much appreciated. I've deployed it on our server already and it works great :)

[davelopez]

Thank you!