layout: Switch to app:tint inplace of android:tint

Resolves multiple lint errors
Signed-off-by: Aayush Gupta <theimpulson@e.email>

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

@@ -426,7 +426,7 @@
                                 android:layout_height="16dp"
                                 android:contentDescription="@string/app_rating_content_description"
                                 android:src="@drawable/ic_app_rating"
-                                android:tint="@android:color/darker_gray"/>
+                                app:tint="@android:color/darker_gray" />
 
                             <TextView
                                 android:layout_width="wrap_content"
@@ -507,7 +507,7 @@
                                 android:layout_height="16dp"
                                 android:contentDescription="@string/app_privacy_score_content_description"
                                 android:src="@drawable/ic_app_privacy"
-                                android:tint="@android:color/darker_gray"/>
+                                app:tint="@android:color/darker_gray" />
 
                             <TextView
                                 android:layout_width="wrap_content"

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

@@ -18,6 +18,7 @@
   -->
 
 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
     android:id="@+id/category_container"
     android:layout_width="match_parent"
     android:layout_height="wrap_content"
@@ -34,8 +35,8 @@
         android:layout_centerVertical="true"
         android:layout_marginStart="@dimen/layout_margin_medium"
         android:src="@drawable/ic_cat_default"
-        android:tint="@color/color_category_icon"
-        android:contentDescription="@string/menu_categories" />
+        android:contentDescription="@string/menu_categories"
+        app:tint="@color/color_category_icon" />
 
     <TextView
         android:id="@+id/category_title"

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

@@ -18,6 +18,7 @@
   -->
 
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
     android:id="@+id/error_container"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
@@ -31,8 +32,8 @@
         android:layout_width="@dimen/app_icon_size"
         android:layout_height="@dimen/app_icon_size"
         android:src="@drawable/ic_error"
-        android:tint="@android:color/darker_gray"
-        android:contentDescription="@string/error_incident" />
+        android:contentDescription="@string/error_incident"
+        app:tint="@android:color/darker_gray" />
 
     <TextView
         android:id="@+id/error_description"

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

@@ -18,6 +18,7 @@
   -->
 
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
     android:id="@+id/splash_container"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
@@ -30,8 +31,8 @@
         android:layout_width="64dp"
         android:layout_height="64dp"
         android:src="@lineageos.platform:drawable/ic_search"
-        android:tint="@android:color/darker_gray"
-        android:contentDescription="@string/menu_search" />
+        android:contentDescription="@string/menu_search"
+        app:tint="@android:color/darker_gray" />
 
     <TextView
         android:layout_width="wrap_content"

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

@@ -18,6 +18,7 @@
   -->
 
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
     android:id="@+id/splash_container"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
@@ -30,8 +31,8 @@
         android:layout_width="64dp"
         android:layout_height="64dp"
         android:src="@drawable/ic_all_apps_updated"
-        android:tint="@android:color/darker_gray"
-        android:contentDescription="@string/menu_updates" />
+        android:contentDescription="@string/menu_updates"
+        app:tint="@android:color/darker_gray" />
 
     <TextView
         android:layout_width="wrap_content"