Replace SHA1 Implementation

Motivation:

The `CNIOSHA1` module from SwiftNIO is an implementation detail. The fact that we were able to import and build the project with it is a bug/feature of Swift Package Manager.

Should the Swift ecosystem standardize on an implementation, that will replace the one we have chosen later.

Modifications:

Use the SHA1 native Swift implementation from CryptoSwift by reproducing the necessary code in our project.
Updates to the appropriate files to provide attribution to CryptoSwift have been included.

Result:
A reliable and pure Swift implementation of the SHA1 digest algorithm in the project for the sake of Lua script cache hashing.