Add supporting themes required for Lotusdocs

themes/twbs/bootstrap/scss/mixins/_text-truncate.scss

@@ -0,0 +1,8 @@
+// Text truncate
+// Requires inline-block or block for proper styling
+
+@mixin text-truncate() {
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}