Create a demo TOM app that contains all the integration points required to customize your tom

[jchate6]

We need some location for example code that tom admin and TOM developers can use to customize their TOM.
Documentation is great, but a demo app that can also serve as a development testbed will be ideal.

• Create demo TOM app repo and include existing integration points #1100
• Build management command for ingesting a disabled version of the demo TOM app #1101
• Add integration points to templates so additional modules can be added without overriding templates #745
• Add Custom App documentation #973
• Add documentation and clarity about how to add templatetags with a custom_app. #1048
• Handling logging output from custom apps installed in a TOM #1083