Adding APIStatsPublisher for publishing stats to BAM

git-svn-id: https://svn.wso2.org/repos/wso2/carbon/platform/trunk@177052 a5903396-d722-0410-b921-86c7d4935375
Removing carbon valve and adding a tomcat valve instead

git-svn-id: https://svn.wso2.org/repos/wso2/carbon/platform/trunk@177053 a5903396-d722-0410-b921-86c7d4935375