Basic pluto with IKEv2 using PSK on the initiator (west), and on the responder.

This is to verify we can use SHA2 for ESP, specifically esp=aes-sha2

sha2 is an alias for sha2_256

See https://tools.ietf.org/html/rfc4868#section-2.6

sha2_128 is not legal, sha2_256 means use 256/2=128 bits)