Improve Tomcat codebase - Managed

After the Tomcat Container code clean up, tomcat-common, it seems all the Managed Tomcat containers are identical both in impl and configuration.

We can create a similar tomcat-common-managed that will have the common parts between the different versions.

{note}
If Tomcat Managed 5.5, 6 and 7 are identical, why do we have 3 versions? {note}