Add optional shape check to data parser

[lemmon-714]

as per #126

The core functionality stays the same, just refactored it since the branching got too big.
Deno tests run through, but I didn't add any of myself yet.

[lemmon-714]

testing rn

[lemmon-714]

Added property tests; succeeds

[lemmon-714]

I'm rn adding the option to leave the lengths of lists/maps/constr-fields indeterminate, so no need to rush looking at it. Also have a hunch it's a bad approach in the first place, will see.

[lemmon-714]

Note that the regular tests - for the old stuff - still run. Still WIP ofc.

[lemmon-714]

Note on the last one: only works on lists of primitives thus far EDIT but that's half a testing issue, depending how you look at it. Requires rn all inner containers to be equally sized, can be interpreted as not a bug.

[lemmon-714]

Works, only thing untested now is the strange SumType Shape thing. And containers of nonprimitives.

[GGAlanSmithee]

I pulled this branch locally and tested it. I don't have any meaningful or productive feedback at this point, but it's building and all tests are passing!

[lemmon-714]

The UInt8Array-tests still fail btw, which is almost certainly a testing-issue, not an implementation-issue.

[lemmon-714]

Come to think of it, it might be simpler to leave the existing parsing as it was before, and add my checks afterwards as a function PlutusData, Shape -> PlutusData.

[lemmon-714]

Refactor in order.

[lemmon-714]

Result #132