feat(calculateInPlacePosition): implement verticalPosition "auto"

[velrest]

The ember-power-select documentation mentions, that the argument verticalPosition is by default auto and therefor the positioning will be automatically calcualted based on available space. This is correct for wormhole positioning but not if the argument renderInPlace={{true}} is used as this is not implemented here in ember-basic-dropdown.

I was not sure if this is a bug or rather a new feature in the scope of ember-basic-dropdown.

Reference

Reproduction: https://github.com/velrest/render_in_place_reproduction

https://ember-power-select.com/docs/api-reference In case page is updated this was the content: