feat(crypto-utils): using base64 encoding for strings from now on, saving much space in the encrypted strings

feat(crypto-utils): using base64 encoding for strings from now on, saving much space in the encrypted strings

Chore(main): Moved all cryptographic operations to a separate library to follow krichoff's principle

feat(server): Server implementation

See merge request !3

feat(client): Client implementation

See merge request !2