Add vue component for save button and integrate into FormMixin

js/components/save_button.js

@@ -0,0 +1,18 @@
+export default {
+  name: 'savebutton',
+
+  props: {
+    text: String,
+    disabled: Boolean,
+    classes: String,
+  },
+
+  data: function() {
+    return {
+      displayClasses: `usa-button usa-button-primary ${this.classes}`,
+    }
+  },
+
+  template:
+    '<button type="submit" :class="displayClasses" tabindex="0" :disabled="disabled">{{ text }}</button>',
+}