[Devstackpy] reorganizing installation directory to support multiple hosts

[Doug Hellmann <doug.hellmann@xxxxxxxxxxxxx>]

I want to reorganize the way files are written to the installation directory to support multiple hosts and reusing existing git repositories. Here's what I have in mind, with host1 set up to run all of the apps and host2 configured as a compute node.

install_root/

    install/

       host1/

         app1/

           traces/

           config/

         app2/

           traces/

           config/

         nova/

           config/

           instances/

           traces/

       host2/

         nova/

           config/

           instances/

           traces/

     source/

       app1/

       app2/

I also plan to add another option for the source tree checkout so that it can be outside of the install_root directory entirely.

I'm looking for feedback before I implement this today or tomorrow, so please let me know what you think.

Thanks,

Doug