[Toolkit][Shadcn] Add DropdownMenu component

[daFish]

Q	A
Bug fix?	no
New feature?	yes
Deprecations?	no
Documentation?	yes
Issues	Tracked in #3233
License	MIT

Add DropdownMenu as a component with support for checkboxes, radio group, and dialog. It utilizes the already available components like Kbd and Dialog. The Button Group component is also updated to use the new component.

ref: https://ui.shadcn.com/docs/components/dropdown-menu

[daFish]

I have also added support for dropdown-menu in button group.

/cc @bernard-ng

[Kocal]

Hi!

I started to look at your work, and thanks you so much for that!

However, I find there is too much logic in the dropdown_menu_controller.js, and I feel like it could be super-simplified by using these new features:

• https://developer.chrome.com/blog/command-and-commandfor
• https://developer.mozilla.org/en-US/docs/Web/CSS/Guides/Anchor_positioning?

Thanks!

[daFish]

@Kocal How to handle custom styles? Should I import them in the controller or is this something to be handled in user land?

[Kocal]

Hey!

Sorry for the long delay, but I've been pretty busy with #3299, which added a tons of changes for documentation and code examples. 😅

They are now shared between this repo and https://github.com/symfony/ux.symfony.com

I will review your PR when possible, can you apply the changes in the meantime?

Thanks! 🙏🏻

[daFish]

@Kocal No worries, Hugo. I just rebased but missed out on the changes you pushed. 😬

[Kocal]

Looks like something wrong happened when rebased 😱

Don't worry, I will take it from here, thanks for your contribution :)

[daFish]

@Kocal Thanks. I think I messed up the rebase because I didn't expected new commits in this PR and I force pushed from my side.