improve guided setup wizard

[synfinatic]

• No longer crash if user hits ^D
• Leading and trailing spaces are now skipped
• Number of questions is dramatically reduced without --advanced flag

Fixes: #530
Fixes: #531

[codecov]

Codecov Report

Merging #532 (15bbe1d) into main (76ef940) will not change coverage.
The diff coverage is n/a.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #532   +/-   ##
=======================================
  Coverage   80.60%   80.60%           
=======================================
  Files          24       24           
  Lines        2882     2882           
=======================================
  Hits         2323     2323           
  Misses        492      492           
  Partials       67       67           

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