pass showKeys as prop to merchant-details child and use emit to toggle (#105)

previously, index and its child compoment merchant-details had their own
booleans and their values were not synched. Using a prop avoids this
problem

static/components/merchant-details/merchant-details.html

@@ -15,7 +15,7 @@
           >
         </q-item-section>
       </q-item>
-      <q-item @click="toggleMerchantKeys" clickable v-close-popup>
+      <q-item @click="toggleShowKeys" clickable v-close-popup>
         <q-item-section>
           <q-item-label v-if="!showKeys">Show Keys</q-item-label>
           <q-item-label v-else>Hide Keys</q-item-label>