[AB-296] adding support for buttons

adding buttons for message embed via feature mode

abstracto-application/abstracto-modules/link-embed/link-embed-impl/pom.xml

@@ -44,6 +44,11 @@
             <version>${project.version}</version>
         </dependency>
 
+        <dependency>
+            <groupId>com.google.code.gson</groupId>
+            <artifactId>gson</artifactId>
+        </dependency>
+
         <dependency>
             <groupId>dev.sheldan.abstracto.core</groupId>
             <artifactId>metrics-int</artifactId>