Wrappers for some of OpenSSL's crypto hash functions

Wrappers for some of OpenSSL's crypto hash functions

Summary:
[Folly] Wrappers for some of OpenSSL's crypto hash functions.

Wraps some of the OpenSSL crypto hash functions with variants that take `ByteRange` for input and `MutableByteRange` for output, and also variants that take `const IOBuf&` for input as well.

These are a bit nicer to use than passing pointers and lengths separately.

Reviewed By: ivmaykov

Differential Revision: D3434562

fbshipit-source-id: 3688ef11680a029b7664ac417a7781e70f9c6926