[Spike] Swappable architecture

[ju-liem]

The idea of a swappable architecture to allow people to use as much or as little of the library as they want/need -- while still offering an all-in-one package -- has been discussed a few times. Before we can decide if we want to take on this work, we need to do some experimentation to understand the size and impact of the undertaking.

[jcmeloni-usds]

@annekainicUSDS @dmethvin-gov Did you do the spike or is it in progress? Are there notes somewhere about where you stand with it or what your thoughts were? Even just "we decided to punt for now and support RR4" is fine!

[annekainicUSDS]

There are a few things we can document in here:

1. When we drew the diagram of the code base on the white board in the basement of JP, we had taken pictures of it and I think @ju-liem was going to use some Microsoft magic to turn those pictures into readable text or graphs that would make it easier for us to document, but I'm not sure where that went. If it doesn't exist, I can just upload the raw photos and hopefully my writing is decipherable.
2. One of the things are actively working on, which is part of the swappable architecture question, is pulling out routing (Move routing functionality to starter app #257), which is going to encompass some other feature requests we've heard from folks as well (removing containing elements like headers, footers, navigation, etc.)

Once we finish tackling 2, we might want to reach back out to some of the teams that specifically requested that functionality (here's one!) to see if it meets their needs. After that we can revisit this issue to see if there are remaining things that could be made "swappable" that have been requested.

[annekainicUSDS]

We now have tickets to cover the individual elements within this spike, closing this ticket.