feat(QML): add basic DnD Deck interface

[acolombier]

Partially addresses #14523 and #14524. Serialisation of edited decks to come in #14539

Screencast.From.2025-05-26.03-52-57.mp4

Notes:

• The ability to remove elements from the deck will come in follow up PR. This will allow better experience on smaller screen
• The bouncing animation won't be kept long term, but for now it help assessing the well functioning resizing/position

[acolombier]

This PR is a little bit large as it adds all the basic deck component, but doesn't bring any new C++ code so hopefully won't be too hard to review!

[JoergAtGithub]

This looks like a workaround. Isn't this a generic functionality, that should be implemented in Mixxx.ControlProxy?

[acolombier]

It isn't that straightforward unfortunately. The reason for implementing this at the QML level, is that we can leverage property binding so both update (1 then 0) will correctly be reported to the CO slots, unconditionally of the event loop state. I believe this is what that pattern was implemented and is already used in other places.
No doubt that this is hacky tho, so perhaps I can create a follow up issue?