Add support for storage array

In #307 and #310 we implemented basic new account storage structure described in https://github.com/0xPolygonMiden/miden-base/issues/239#issuecomment-1791479475. Specifically, we have support for value types but not for maps or arrays.

We need to add support for arrays as well. This would make storage more efficient and flexible for use cases where a small-sh number of items needs to be index-accessible.

To support this on the kernel side, we need to add two procedures to the kernel API:
```
#! Inputs: [slot, index, ...]
#! Outputs: [VALUE, ...]
#!
#! Fails if the slot contains a simple value or a storage map.
export.get_array_item

#! Inputs: [slot, index, VALUE, ...]
#! Outputs: [OLD_VALUE, ...]
#!
#! Fails if the slot contains a simple value or a storage map.
export.set_array_item
```

We also need to add support for maps to `AccountStorage` as well as `DataStore` trait in `miden-tx`. The backing data structure for this is probably going to be Simple SMT.