Create version 2 of the training

[plocket]

Still just a brainstorm. For review by @aposternak2137 at the moment. Look at the changed files, but only the .yml files. Docassemble changed some plumbing.

I have a lot of thoughts [doubts].

1. I realized I bounced back and forth between changing input type and changing datatype. I think it may be worth switching the order of the fields we introduce, but I'm not sure quite how to do that without making the progress of the interview awkward.
2. I forgot what we said about getting rid of input type for text fields during an early lesson.
3. I'm waffling on introducing the complexity of the full radio button choices as opposed to a simple yesnoradio. If we use yesnoradio, though, I can't think of a way to avoid using an if statement in the Mako on the final screen.
4. I probably have other questions. They should be in the files themselves, in comments that start with 'TODO:'.

[Despite all that, I think we could record the first lesson, along with its exercise.]

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When done:

Trying something a bit different. Edits old lessons and adds new ones. When we're ready, we'll delete the old files.

TODO:

• Add co-authorship when we squash and merge.