[bug] JS & TS don't preserve nested `option<T>`

[JonasKruckenberg]

JS & TS guests decode option<T> types as T | null, this however means that nested options aren't preserved:

option<option<option<T>>> is decoded as T | null | null | null which essentially "flattens" the option into T | null loosing the information about nesting in the process.

This also affects encoding which means that JS & TS guests can't send nested options to the Host so we need to find a solution for this.

[JonasKruckenberg]

This is fixed as of v0.2.0