Add RemoteIpValve

As the Tomcat instance created by this buildpack is always located
behind a proxy, this change adds the RemoteIpValve to the Tomcat
configuration.  This change ensures that functionality such as
HttpServletRequest.isSecure() works properly in the Cloud Foundry
environment.

[#52956737, #8]
Merge 52956737-remote-ip-valve to master

[#52956737]