feat: upgrade to popper 2

[jorenbroekema]

Right now, the tooltip demo that I changed ('has-arrow' attribute added), looks good, for at least placement top and placement right. So basically POC is done.

TODO:

• Check whether modifiers that have the same name get properly deduped by popper. If so, we can just stack them and don't have to do any merging/deduping ourselves. If not, we may have to create a mergeModifiers helper or something.. now that modifiers is an array (not uniquely-keyed items)
• I managed to get quite far with fixing types, but there's still some errors. This will be some work to get it all properly..
• Update Mixin type definition files where needed (ArrowMixin, OverlayMixin)
• Update lion packages that use/extend popperConfig
• Make all tests succeed again
• Update demos (tooltip, overlays etc.)
• Migration guidelines for our users (link to popper migration guidelines probably is enough, since we mirror their API)
• Create popper config compatibility layer in our extension library and test it
• Create changeset release

[changeset-bot]

🦋 Changeset detected

Latest commit: 1f62ed8

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 7 packages

Name	Type
@lion/overlays	Minor
@lion/tooltip	Minor
@lion/combobox	Patch
@lion/dialog	Patch
@lion/input-datepicker	Patch
@lion/select-rich	Patch
@lion/form-integrations	Patch

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