Rename diffie_hellman_t to key_exchange_t and change the interface etc.

This makes it more generic so we can use it for QSKE methods.

src/conftest/hooks/log_ke.c

@@ -48,7 +48,7 @@ METHOD(listener_t, message, bool,
 			{
 				ke = (ke_payload_t*)payload;
 				DBG1(DBG_CFG, "received DH group %N",
-					 diffie_hellman_group_names, ke->get_dh_group_number(ke));
+					 key_exchange_method_names, ke->get_key_exchange_method(ke));
 			}
 		}
 		enumerator->destroy(enumerator);

src/conftest/hooks/set_proposal_number.c

@@ -110,7 +110,7 @@ METHOD(listener_t, message, bool,
 					copy_proposal_algs(proposal, new, ENCRYPTION_ALGORITHM);
 					copy_proposal_algs(proposal, new, INTEGRITY_ALGORITHM);
 					copy_proposal_algs(proposal, new, PSEUDO_RANDOM_FUNCTION);
-					copy_proposal_algs(proposal, new, DIFFIE_HELLMAN_GROUP);
+					copy_proposal_algs(proposal, new, KEY_EXCHANGE_METHOD);
 					copy_proposal_algs(proposal, new, EXTENDED_SEQUENCE_NUMBERS);
 					updated->insert_last(updated, new);
 				}