Add setting to remember download columns width

[heldersepu]

Are you tired of having to resize the columns in the download page all the time? me too...

This PR adds a couple of setting to set column width, for now i prefer to just have it as a "hidden" config option and in future versions we can add it in the UI, and more fancy stuff

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This is how it looks like with my favorite options, I like the name to be the widest and the progress a bit wider than the default

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Here is the new setting:

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My goal is to make small changes as I get myself familiar with the code base, then I would be able to take on some more challenging issues

[github-actions]

Hi @heldersepu, thank you for contributing to Tribler! 🚀

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[egbertbouman]

Thanks for your PR!
Saving the column settings seems like a nice feature to have. However, I don't think these settinge belongs in the core. We normally store GUI settings in self.window().gui_settings. Could you try storing it there?

[heldersepu]

@egbertbouman correction applied... thanks for the tip, code looks simpler that way!
I also rebased and squashed my commits.

[egbertbouman]

Thanks, looks good! I'm fine with merging this PR as-is, but I just noticed that the header also has saveState/restoreState functionality.

If you're up for it, you could save/restore the entire state of the downloads list in TriblerWindow.onClose/TriblerWindow.restore_window_geometry. We're already doing this for the position and size of the window. For instance, saving would be:

self.gui_settings.setValue("download_columns", self.downloads_list.header().saveState())

[heldersepu]

Let me experiment with that self.downloads_list.header().saveState() will let you know more tomorrow

[heldersepu]

@egbertbouman I made the following changes:

• added a new section to the settings page, screenshot provided above
• using the header saveState/restoreState functionality as suggested, (nice bonus it also saves the sort)
• new function on_header_change to save the state if use has it set

only disagreement with your suggestion I'm not saving onclose or restore_window_geometry instead doing it on:

• sectionResized
• sortIndicatorChanged

just in case if we get a crash, the state is not affected because it saved immediately after change

[egbertbouman]

Nice, it's running smoothly and there's even a checkbox for it now 👍
Thanks again!

[heldersepu]

it was fun! ... thanks @egbertbouman for pushing me in the right direction
... if you can, take a look at an issue I opened a few days ago: #8007 would love more eyes on that