Insert new panels should support keyboard navigation

[neos-bot]

Jira issue originally created by user @aertmann:

When opening the insert new panel from either the navigate component or inline handles, the panels options should be navigable with tab, arrow keys and hitting enter/space should select the focussed element.

Jira-URL: https://jira.neos.io/browse/NEOS-340

[neos-bot]

Comment created by @dimaip:

Navigating with arrows up and down is not trivial, as it's just a list of floats.
I'd just define a tabindex for every element, and bind space/enter to select.

[neos-bot]

Comment created by @aertmann:

Well it could just be that left and up goes back and right and down goes forward.

[neos-bot]

Comment created by @kdambekalns:

This is under review, which are the corresponding changes?

[neos-bot]

Comment created by @aertmann:

there isn't any, incorrect status