Add get_scrollbar(position) to access scrollbars by position

[JaskRendix]

PR introduces a new method get_scrollbar(position) that makes it much easier, and cleaner, to grab a scrollbar at a specific position. Previously, the only way to access scrollbars was to reach into the private _scrollbars list and do something like _scrollbars[0]. Not ideal, especially when you don’t want to rely on internal details or remember which index matches which side.

With get_scrollbar(), you can now use a simple position string like "north" or "east" and get exactly what you need. It makes your code more readable and aligns with good encapsulation practices. It also validates the input, so you're less likely to accidentally pass something weird and have it break silently. On top of that, I added a few unit tests to verify the method works correctly across different positions and edge cases, just to be sure it's solid.

[ppizarror]

Thanks!
Let me know when you are ready in your PR initiative to create a new version

[JaskRendix]

@ppizarror sure thing! Just one quick heads-up, while I was poking around the code, I saw that pyproject_update.py and pyproject.toml are listed in the .gitignore. Noticed they haven't been touched in a couple years, so I’m wondering, was that intentional, or were they added by accident? Just want to make sure we’re not missing anything important

[ppizarror]

I remembered adding those as I was playing around with tox and other stuff... but it was several years ago. Feel free to remove them! Thanks a lot for your contributions