Feature Statistics: Disable stretching of distribution column, set minimal width

[janezd]

Issue

Fixes #6983. I think. @ajdapretnar ?

Description of changes

Column distributions was set to stretch, i.e. occupy all extra width. Other columns had a default size (100).

After this, columns have a minimum size of 100, and the distribution column gets no special treatment. Sizes are reasonable. Downside is that they can't be manually reduced below 100.

Includes

• Code changes
• Tests
• Documentation

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 89.02%. Comparing base (246474b) to head (304fb4c).
⚠️ Report is 4 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #7226      +/-   ##
==========================================
- Coverage   89.03%   89.02%   -0.01%     
==========================================
  Files         335      335              
  Lines       74243    74254      +11     
==========================================
+ Hits        66099    66103       +4     
- Misses       8144     8151       +7     

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[ajdapretnar]

I like everything about this, except for the very first column with variable type, which IMO would never be bigger than minimum size. It takes unnecessary space now. I'd make an exception for this column being at absolute minimum, with the other columns as they are now.