Convert from BaseModel to jsonschema + TypedDict

[evalott100]

Closes #337

[evalott100]

Will probably streamline the system of adding extra json schema to BaseModels too

[coretl]

I'm happy with this, and it didn't require any code changes so I think that means the checking for nulls is OK.

@danielballan please can you review the schema changes on projections?

Just to make sure, please can you point bluesky to this and run mypy src/bluesky, then point ophyd-async at this and run pyright src/ophyd_async and check it doesn't think we need to check for nulls anywhere?

[coretl]

Also, why is the test failing?

[evalott100]

Also, why is the test failing?

There wasn't consistency in the order of the generated __init__.py so the test for consistency in regeneration failed. Sorted them now.

I'll wait for a review and then add an ADR and update the docs within this PR once we've decided.

[evalott100]

I tested that it's working against bluesky and ophyd-async, both tests and type checking.

I had to write some custom code to include Partial documents within the jsonschema itself:

event-model/src/event_model/generate/create_documents.py

Line 169 in 2195892

if refs:

[danielballan]

Looks good.

Incidentally I like the new usage, too. Good use of python -m ....

[evalott100]

Was going to add tests for the BaseModel themselves. I think it's better to do it in a different PR though.