Build management command for ingesting a disabled version of the demo TOM app

[jchate6]

We currently build a custom_code app during tom_setup.
This is based on a generic template and includes an example of extending the Target model.
Instead this should copy the demo app described in #1099 and disable its integration points so they can be activated manually.

We should develop a start_tom_app management command that will do these things and is called in tom_setup.