Deconstruct `AccountComponentCode`'s library into components

https://github.com/0xMiden/miden-base/pull/2142 introduces the concept of `AccountComponentCode`, which currently just wraps a `Library`. We could deconstruct its library into its components, providing getters where necessary:

> Probably not for this PR, but I think we should deconstruct `Library` into relevant components here - similar to how ?we do this for `NoteScript` and `TransactionScript`. It could look something like:
>
> ```rust
> pub struct AccountComponentCode {
> mast: Arc,
> exports: Vec,
> }
> ```
_Originally posted by @bobbinth in https://github.com/0xMiden/miden-base/pull/2142#discussion_r2611894494_