Add policy and policy config

[vincenthz]

Need to add policy settings for RSA key size, DH key size, types of ciphers and public suffix list.

One of the issue of the public suffix list is that it's a dynamically updated list, so there's the issue on how do we provide it to the user, and if we allow updating, etc.

And then we need a policy config (in system or user directory for example) that would allow:

• certificate pinning per host
• overriding crypto size bounds and cipher list per host or globally
• default version choice per host
• public suffix overriding

[Porges]

It would make sense for the public suffix list to be its own package so it can be updated independently.