Add dummy app back for development (#3229)

* Add dummy app back for development

* Ignore dummy for linting

Author: RobbieTheWagner

.eslintignore

@@ -2,6 +2,7 @@
 /cypress/dummy/js/prism.js
 /dist/
 /docs/
+/dummy/
 /landing/
 /site/
 /test/cypress/dummy/

shepherd.js/.eslintignore

@@ -1,2 +1,3 @@
 /dist/
+/dummy/
 /tmp/

shepherd.js/.prettierignore

@@ -1 +1,2 @@
-/dist/
+/dist/
+/dummy/

shepherd.js/dummy/assets/favicons/android-chrome-192x192.png

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<browserconfig>
+    <msapplication>
+        <tile>
+            <square150x150logo src="/mstile-150x150.png"/>
+            <TileColor>#00aba9</TileColor>
+        </tile>
+    </msapplication>
+</browserconfig>