Uses the crypt() function to do password encryption. This function handles
several schemes such as: MD5, Blowfish, SHA1, SHA2.
SHA-512 is used in Authelia for best security.
The algorithm is fully described in
https://www.akkadia.org/drepper/SHA-crypt.txt
The 'crypt3' npm package has been added as a dependency to use the crypt()
function. The package needs to be compiled in order to call the c function,
that's why python, make and C++ compiler are installed temporarily in the
Docker image.