remove keycloak, refactor packages (#2963)

spring-boot/pom.xml

@@ -24,10 +24,6 @@
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-web</artifactId>
         </dependency>
-        <dependency>
-    <groupId>org.keycloak</groupId>
-    <artifactId>keycloak-spring-boot-starter</artifactId>
-</dependency>
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-data-jpa</artifactId>
@@ -172,17 +168,6 @@
             <artifactId>artemis-server</artifactId>
         </dependency>
     </dependencies>
-    <dependencyManagement>
-  <dependencies>
-    <dependency>
-      <groupId>org.keycloak.bom</groupId>
-      <artifactId>keycloak-adapter-bom</artifactId>
-      <version>3.3.0.CR2</version>
-      <type>pom</type>
-      <scope>import</scope>
-    </dependency>
-  </dependencies>
-</dependencyManagement>
 
     <build>
         <finalName>spring-boot</finalName>
@@ -282,7 +267,7 @@
 
     <properties>
         <!-- The main class to start by executing java -jar -->
-        <start-class>org.baeldung.boot.DemoApplication</start-class>
+        <start-class>org.baeldung.demo.DemoApplication</start-class>
         <spring.version>4.3.4.RELEASE</spring.version>
         <git-commit-id-plugin.version>2.2.1</git-commit-id-plugin.version>
         <jquery.version>3.1.1</jquery.version>