Configuration of list of cipher suites allows a user to disable use
of weak ciphers or continue to support them for legacy usage if they
so choose.

List of available cipher suites at:
https://golang.org/pkg/crypto/tls/#pkg-constants



Default cipher suites have been updated to:
- TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384
- TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
- TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305
- TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305
- TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256
- TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256
- TLS_AES_128_GCM_SHA256
- TLS_CHACHA20_POLY1305_SHA256
- TLS_AES_256_GCM_SHA384

MinimumTLS has also been updated to include TLS 1.3 as an option
and now defaults to TLS 1.2 since 1.0 and 1.1 have been deprecated.
Signed-off-by: David Luu <david@davidluu.info>