Add relaxed/very-relaxed versions of celled grid

src/definitions/collections/grid.less

@@ -622,7 +622,6 @@
 .ui.celled.grid > .column:not(.row),
 .ui.celled.grid > .row > .column {
   display: table-cell;
-  padding: 0.75em;
   box-shadow: (-@celledWidth) 0px 0px 0px @celledBorderColor;
 }
 .ui.celled.grid > .column:first-child,
@@ -633,6 +632,19 @@
   box-shadow: none;
 }
 
+.ui.celled.grid > .column:not(.row),
+.ui.celled.grid > .row > .column {
+  padding: @celledPadding;
+}
+.ui.relaxed.celled.grid > .column:not(.row),
+.ui.relaxed.celled.grid > .row > .column {
+  padding: @celledRelaxedPadding;
+}
+.ui[class*="very relaxed"].celled.grid > .column:not(.row),
+.ui[class*="very relaxed"].celled.grid > .row > .column {
+  padding: @celledVeryRelaxedPadding;
+}
+
 /* Internally Celled */
 .ui[class*="internally celled"].grid {
   box-shadow: none;

src/themes/packages/default/collections/grid.variables

@@ -80,6 +80,9 @@
 @celledWidth: 1px;
 @celledBorderColor: @solidBorderColor;
 
+@celledPadding: 0.75em;
+@celledRelaxedPadding: 1em;
+@celledVeryRelaxedPadding: 2em;
 
 /*--------------
     Stackable