Improve (usability of) the condition element

Zur Orientierung siehe z.B. Condition bei CommCare HQ [1, 2] und Filter bei ProtonMail [3].

[1] https://www.commcarehq.org/demo/
[2] https://help.commcarehq.org/display/commcarepublic/Common+Logic+and+Calculations
[3] https://protonmail.com/support/knowledge-base/filters/