Hashbase

- Merged the implementation of SHA-512/224, SHA-512/256 and SHA-384 with SHA-512
- Optimized the imports

- Added the following hash functions:
- SHA-512/224 (`hashbase.SHA512_224`)
- SHA-512/256 (`hashbase.SHA512_256`)

- Added the following hash functions:
- SHA-384 (`hashbase.SHA384`)
- SHA-512 (`hashbase.SHA512`)
- Modified the `modular_add`, `rotate_left`, `rotate_right`, `shift_left` and `shift_right` utility functions to handle 32-bit and 64-bit numbers
- Modified the `apply_message_padding` utility for more flexible padding

- Added the following hash function:
- SHA-224 (`hashbase.SHA224`)

- Minor docstring update

- Added the following hash function:
- SHA-256 (`hashbase.SHA256`)
- Added utilities for `rotate_left`, `rotate_right`, `shift_left` and `shift_right`
- Updated the `utils.modular_add()` function