Use Editing Side-Panel in Talent Trees to Set Requirements Instead of Popup Menu

[Khunkurisu]

Is your feature request related to a problem? Please describe.
Somewhat tied to #247, but only tangentially. Would technically also solve it.

Describe the solution you'd like
Effectively all I'm suggesting is that the configuration side-panel in the Talent Tree when selecting a Talent goes mostly unused. Instead of the + button forming a popup, simply have separate lists for each option in the Select Menu and the + button just automatically creates an entry for that type. The visual real-estate is there, it won't cause too much clutter as there's only a handful of requirements on a given talent, and an in-line set of fields/select menus is easier to work with.

Describe alternatives you've considered
What we have now works fine, but the workflow is a bit stilted because of the constantly changing cursor focus.

Version
0.3.0

Additional context
Effectively I am suggesting to make this dialogue:

Appear as an inline row here:

Checklist:

• I have searched the existing issues to ensure this feature has not already been requested.