docs(demos): fix demos to have same class name and remove files that aren't needed anymore

references #5311

demos/button/index.ts

@@ -0,0 +1,6 @@
+import {App} from 'ionic/ionic';
+
+@App({
+  templateUrl: 'main.html'
+})
+class ApiDemoApp {}

demos/button/main.html

@@ -0,0 +1,64 @@
+
+<ion-toolbar>
+  <ion-title>Button</ion-title>
+</ion-toolbar>
+
+<ion-content text-center>
+
+  <h4>Colors</h4>
+
+  <button>Default</button>
+
+  <button secondary>Secondary</button>
+
+  <button danger>Danger</button>
+
+  <button light>Light</button>
+
+  <button dark>Dark</button>
+
+  <h4>Shapes</h4>
+
+  <button full>Full Button</button>
+
+  <button block>Block Button</button>
+
+  <button round>Round Button</button>
+
+  <button fab style="position: relative;">FAB</button>
+
+  <h4>Outlines</h4>
+
+  <button secondary full outline>Outline + Full</button>
+
+  <button secondary block outline>Outline + Block</button>
+
+  <button secondary round outline>Outline + Round</button>
+
+  <button secondary fab outline style="position: relative;">FAB</button>
+
+  <h4>Icons</h4>
+
+  <button dark>
+    <ion-icon name="star"></ion-icon>
+    Left Icon
+  </button>
+
+  <button dark>
+    Right Icon
+    <ion-icon name="star"></ion-icon>
+  </button>
+
+  <button dark>
+    <ion-icon name="star"></ion-icon>
+  </button>
+
+  <h4>Sizes</h4>
+
+  <button light large>Large</button>
+
+  <button light>Default</button>
+
+  <button light small>Small</button>
+
+</ion-content>