feature: use avaliable space if first sub is too large

[birdspider]

hi,

I would need something like this, do you want it upstreamed or should I maintain this separately ?

Feedback is also welcome.

Regards

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this shifts long subs sideways and up/down into available space (is easily visible in the configurator by using a small vh and opening "Long-Sub")

EDIT: I should add, this is in response to scroll not being implemented (yet?) in sm2.0 (in sm1.0 there was an up/down icon which shifted the items), if scroll gets implemented (I could help a bit) - this PR may be unnecessary

[vadikom]

Yep, indeed, my idea was to implement some kind of scroll later (most probably as an addon/extension since I realized this is quite a bit of code most users won't need).

The problem with a generic solution like yours is that when auto-lifted up the sub usually covers some of the sibling main menu items right away.