piket_client.gui: Set maximum number of columns, use sqrt

piket_client/gui.py

 import logging
 import os
 import sys
+from math import ceil, sqrt
 
 import qdarkstyle
 
         LOG.debug("Initializing NameButtons.")
 
         ps = Person.get_all(True)
-        num_columns = round(len(ps) / 10) + 1
+        # num_columns = round(len(ps) / 10) + 1
+        num_columns = min(5, ceil(sqrt(len(ps))))
 
         if self.layout:
             LOG.debug("Removing %s widgets for rebuild", self.layout.count())