Add margin for grid layout

Signed-off-by: alperozturk <alper_ozturk@proton.me>

app/src/main/res/layout/grid_image.xml

@@ -21,6 +21,8 @@
     xmlns:app="http://schemas.android.com/apk/res-auto"
     android:id="@+id/ListItemLayout"
     android:orientation="vertical"
+    android:layout_marginEnd="@dimen/grid_container_margin"
+    android:layout_marginTop="@dimen/grid_container_margin"
     android:gravity="center"
     android:layout_width="match_parent"
     android:layout_height="@dimen/grid_container_height">

app/src/main/res/layout/grid_item.xml

@@ -20,6 +20,8 @@
     xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"
     android:id="@+id/ListItemLayout"
+    android:layout_marginEnd="@dimen/grid_container_margin"
+    android:layout_marginTop="@dimen/grid_container_margin"
     android:orientation="vertical"
     android:gravity="center"
     android:layout_width="match_parent"

app/src/main/res/values/dims.xml

@@ -108,6 +108,7 @@
     <dimen name="activity_row_layout_height">48dp</dimen>
     <dimen name="notification_icon_width">24dp</dimen>
     <dimen name="notification_icon_height">24dp</dimen>
+    <dimen name="grid_container_margin">4dp</dimen>
     <dimen name="grid_container_width">130dp</dimen>
     <dimen name="grid_container_height">120dp</dimen>
     <dimen name="grid_filename_width">80dp</dimen>