Add text2speech to library (scratchfoundation#3423)

Author: ericrosenbaum

src/lib/libraries/extensions/index.jsx

@@ -8,6 +8,7 @@ import translateImage from './translate.png';
 import microbitImage from './microbit.png';
 import ev3Image from './ev3.png';
 import wedoImage from './wedo.png';
+import text2speechImage from './text2speech.png';
 
 import microbitPeripheralImage from './peripheral-connection/microbit/microbit-illustration.svg';
 import microbitMenuImage from './peripheral-connection/microbit/microbit-small.svg';
@@ -75,6 +76,25 @@ export default [
         ),
         featured: true
     },
+    {
+        name: (
+            <FormattedMessage
+                defaultMessage="Text to Speech"
+                description="Name for the Text to Speech extension"
+                id="gui.extension.text2speech.name"
+            />
+        ),
+        extensionId: 'text2speech',
+        iconURL: text2speechImage,
+        description: (
+            <FormattedMessage
+                defaultMessage="Make your projects talk."
+                description="Description for the Text to speech extension"
+                id="gui.extension.text2speech.description"
+            />
+        ),
+        featured: true
+    },
     {
         name: (
             <FormattedMessage