Simplify multitest storage

[ethanfrey]

merge after #334

Major overhaul of how storage and caching works in multi-test.
This should allow for much more extensibility in multi-test in the future

[ethanfrey]

Okay, this massive PR is ready for review.

It is a quasi-rewrite of the internals of multi-test, keeping a very similar API.

I think it makes everything much clearer and extensible, and lays the groundwork to easily add more "Keepers" to mock out staking, or handle custom messages

[maurolacy]

Can you add some context / description of the changes? It is impossible for me to review this in any meaningful way. Too many changes, that are unrelated, or at least, difficult to relate to the previous code base.

[ethanfrey]

Can you add some context / description of the changes? It is impossible for me to review this in any meaningful way. Too many changes, that are unrelated, or at least, difficult to relate to the previous code base.

Yeah, I would just review the new codebase, and not the diff.
I will write a docs.rs file explaining the new architecture, then ask for a re-review.

The comments above were helpful to identify that.

[ethanfrey]

@maurolacy I added a DESIGN.md file that should help.

I would not review the diff, but rather review the new code by itself. You can add comments on the diff, but this is basically a re-write, so it makes more sense to look at it as a whole.

test_helpers, transactions, and contracts rust files are more or less unchanged.
bank, wasm, app and executor are > 50% modified

[maurolacy]

@maurolacy I added a DESIGN.md file that should help.

Thanks. I'll take a look.

[maurolacy]

Reviewed the DESIGN doc.

[maurolacy]

lgtm, but this is still above my head. Need to get more exposure to both using and modifying / extending multi-test.

[ethanfrey]

Thanks for the feedback. I will update and merge.
There are a number of smaller steps in the next few weeks to get this closer to the vision