OpenID Connect support (#865)

* Added OpenID Connect support

Utilized Spring Security's OAuth2 respectively OIDC support as another
possibility to manage users and their permissions.

Signed-off-by: Brandon Schmitt <Brandon.Schmitt@kiwigrid.com>

* Document OpenID Connect Support

Signed-off-by: Brandon Schmitt <Brandon.Schmitt@kiwigrid.com>

* Updated license in OidcUserManagementAutoConfiguration.java

Signed-off-by: Brandon Schmitt <Brandon.Schmitt@kiwigrid.com>

* Revert updated license notice and add Kiwigrid license file

This reverts commit 23d36245

Signed-off-by: Brandon Schmitt <Brandon.Schmitt@kiwigrid.com>

* Resolve SonarQube issues

- Explicitly import the needed specific classes
- Document public methods
- Add `static` to the constant `JwtAuthoritiesOidcUserService.INVALID_REQUEST`
- Remove superfluous runtime exception `OAuth2AuthenticationException`

Signed-off-by: Brandon Schmitt <Brandon.Schmitt@kiwigrid.com>

* Add OidcUser support in SpringSecurityAuditorAware

Signed-off-by: Brandon Schmitt <Brandon.Schmitt@kiwigrid.com>

* Secure Management API using OpenID Connect, too.

Signed-off-by: Brandon Schmitt <Brandon.Schmitt@kiwigrid.com>

hawkbit-ui/pom.xml

@@ -201,6 +201,14 @@
          <groupId>org.springframework.security</groupId>
          <artifactId>spring-security-web</artifactId>
       </dependency>
+      <dependency>
+         <groupId>org.springframework.security</groupId>
+         <artifactId>spring-security-oauth2-client</artifactId>
+      </dependency>
+      <dependency>
+         <groupId>org.springframework.security</groupId>
+         <artifactId>spring-security-oauth2-jose</artifactId>
+      </dependency>
 
       <dependency>
          <groupId>com.vaadin</groupId>