clean-up dependencies between webserver modules

leverage transitive dependencies to simplify dependencies

server/sonar-webserver-core/build.gradle

@@ -44,7 +44,6 @@ dependencies {
   compile project(':server:sonar-process')
   compile project(':server:sonar-server-common')
   compile project(':server:sonar-webserver-api')
-  compile project(':server:sonar-webserver-auth')
   compile project(':server:sonar-webserver-es')
   compile project(':sonar-core')
   compile project(':sonar-duplications')

server/sonar-webserver-webapi/build.gradle

@@ -18,7 +18,6 @@ dependencies {
   compile project(':server:sonar-ce-task')
   compile project(':server:sonar-db-dao')
   compile project(':server:sonar-process')
-  compile project(':server:sonar-webserver-auth')
   compile project(':server:sonar-webserver-es')
   compile project(':server:sonar-webserver-ws')
   compile project(':sonar-scanner-protocol')