Add support for Apple Password Rules

[mitchchn]

We should be able to produce a recipe from a password rules string. Both the character and wordlist generators could support this, returning an error if the supplied requirements are outside the constraints of the generator.

[dolmen]

This feature could be built in an other Go package that would use spg as its backend.

No need to extend the spg API.

[dolmen]

Related project: https://github.com/1Password/password-rules-parser