feat(lib): add input for intersection mode

[PhOder]

This commit adds a new @Input() property intersectionMode to the SelectContainerComponent that allows to modify if items' bounding boxes need to be fully included in the select box or (by default) if bounding boxes need to intersect.

[PhOder]

Hi @d3lm =)
In this PR I'd like to suggest a new input property as described above.

I'm unsure about the naming with the available options for this:
@Input() intersectionMode: 'intersection' | 'included' = 'intersection';