SquotGUI: Use new UIManager interface (#chooseOptionsFrom:...) for Squeak 6.0+

[LinqLover]

Complements ToolBuilder-Kernel-tpr.157: When available, use modern #chooseOptionFrom:title: from UIManager instead of the classical #chooseFrom:title: that is intended for data only.

This restores the correct look for several dialogs, which looked not so nice recently:

Now they look beautiful again:

Note that I decided against using the options variant for choosing artifacts/remotes which are typically a small number of items only, but still arbitrary data, so we can't be sure about the exact number:

Twin PR of https://github.com/hpi-swa/smalltalkCI/pull/555.

[j4yk]

Thank you!