Add search bar for the soundfont player

[yohannd1]

The goal of this PR is to make searching for patches easier in the built-in soundfont player.

With this PR selecting a patch should be made easier, and at least for the first bank you can pretty much do most of it with just the keyboard (e.g. to pick patch "Shamisen", open the dialog, type "Sha", press enter, and you're good to go).

Closes #8023.

To-do list:

• Initial implementation - working search bar, implemented referencing the work done on the effect picker search bar.
• Make sorting on the patch column work properly (it's doing string sorting instead of sorting by the numeric value)

This PR is ready for review!

[bratpeki]

Done with the code review. Just increase the rowHeight, if you agree it should be increased, and if it's necessary initialize and clear the m_selProg value.

[bratpeki]

Also, to add, I set m_selProg to -1 instead of 0 purely to account for when there's no programs in the SF2 bank.

However, when you open the selection dialogue, it always selects the first item, so m_selProg is 0 then, and not -1.

If you know setting it to 0 doesn't break anything, feel free to do so.

[yohannd1]

You're right about m_selProg, so I decided to set it to 0. I don't think it breaks anything, indeed, and -1 probably could break more (even though in the code I made I don't think that value was ever set). I also went and moved some initializations to the member initializer list to follow style guidelines.

As for the row height, just updated it as well. I think I used a smaller value to try and align the bank list items (and to be fair, it doesn't even really do that), but making text readable is of higher priority.

[bratpeki]

Approved for code and testing.

[messmerd]

I started this review a couple weeks ago but didn't submit it for some reason. So here it is.

[yohannd1]

Suggestions applied! And I did a bit more refactoring.