Fernetcrypt

This is a documentation-only release, adding the full usage to the README.

- Add "edit" command to edit an encrypted file in place.
- Made "output file" optional, if not specified it uses the input file, adding the ".fernet" suffix if encrypting or removing whatever "." suffix if decrypting.
- Converted argument parsing to "typer" .

This is the same code as 1.0.0 but with 3.12 tagged in the matrix.

A simple fernet encryption CLI to allow encrypting/decrypting files given a password. This implements both a "raw" format consisting only of the salt and the encrypted data, blocked in 40,960 byte chunks, and a "uPlaybook" format which uses an ASCII encoded version of the salt and adds a file format identifier magic number.