Devolutions-crypto

- Removes the `derive_keypair` function as it was not used and was broken.
- Added `constant_time_equals` in the utils.

Added
- Added the `signing_key` and `signature` modules to support public key signing using ed25519.

Added
- Added `scrypt_simple` to Rust and C

Changed
- Fixed missing file in NPM package

Added
- Added `derive_key_argon2()` method to derive a symmetric key from a set of `Argon2Parameters`.

Changed
- Renamed `derive_key()` to `derive_key_pbkdf2()`.

Changed
- Fixes for Internet Explorer and Safari.

Added (C)
- Added a legacy decryption handler, in case the header is invalid.

Added (WASM)
- Binded a Rust Scrypt method to WASM for a very specific use case, and this might be removed in the future, so don't rely on it.