feat(corelib): ByteArrayFromIterator

[julio4]

Implement iter::FromIterator<ByteArray, u8>

Example

let iter = array!['h', 'e', 'l', 'l', 'o'].into_iter();
let ba: ByteArray = FromIterator::from_iter(iter);
assert_eq!(ba, "hello");

[reviewable-StarkWare]

This change is 

[orizi]

Reviewed 2 of 2 files at r1, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @julio4)

---

a discussion (no related file):
@gilbens-starkware for 2nd eye.

---

corelib/src/test/byte_array_test.cairo line 498 at r1 (raw file):

fn test_from_iterator() {
    let ba: ByteArray = FromIterator::from_iter(array!['h', 'e', 'l', 'l', 'o'].into_iter());
    assert_eq!(ba, "hello");

Suggestion:

    let ba: ByteArray = array!['h', 'e', 'l', 'l', 'o'].into_iter().collect();
    assert_eq!(ba, "hello");

[julio4]

Reviewable status: 0 of 2 files reviewed, 1 unresolved discussion (waiting on @orizi)

---

corelib/src/test/byte_array_test.cairo line 498 at r1 (raw file):

fn test_from_iterator() {
    let ba: ByteArray = FromIterator::from_iter(array!['h', 'e', 'l', 'l', 'o'].into_iter());
    assert_eq!(ba, "hello");

Done.

[orizi]

Reviewed 2 of 2 files at r2, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @julio4)