XDOCKER-15: Reorganize directory structure to remove the need for branches

xwiki-mysql-tomcat/.dockerignore

xwiki-mysql-tomcat/.env

xwiki-mysql-tomcat/Dockerfile

xwiki-mysql-tomcat/docker-compose-using.yml

xwiki-mysql-tomcat/docker-compose.yml

xwiki-mysql-tomcat/mysql/xwiki.cnf

xwiki-mysql-tomcat/tomcat/setenv.sh

xwiki-mysql-tomcat/xwiki/docker-entrypoint.sh

xwiki-mysql-tomcat/xwiki/hibernate.cfg.xml