Creates a native endian integer value from its representation as a byte array in big endian.
# Examples
Basic usage:
```
# use ::exint::primitive::*;
# ::exint::uint! {
use exint::Saturating;
assert_eq!(Saturating::<u24>::from_be_bytes([0x12, 0x34, 0x56]), Saturating(0x123456_u24));
# }
```