Adjust spacing

PersonListCard.fxml: Adjust spacing in HBox

The spacing attribute for HBox in PersonListCard.fxml is set to '5',
causing it to look like a double-whitesspace is present in the Person List
Card (e.g. 1.  John)

Let's change the spacing attribute of the HBox in
PersonListCard.fxml to 0.5, so that it looks like a single whitespace
is present instead of double (e.g. 1. John).

src/main/resources/view/PersonListCard.fxml

@@ -18,7 +18,7 @@
       <padding>
         <Insets top="5" right="5" bottom="5" left="15" />
       </padding>
-      <HBox spacing="5" alignment="CENTER_LEFT">
+      <HBox spacing="0.5" alignment="CENTER_LEFT">
         <Label fx:id="id" styleClass="cell_big_label">
           <minWidth>
             <!-- Ensures that the label text is never truncated -->