Add aead IETF constructions

Since the chacha20poly1305 constructions were the IETF variants,
we renamed those so they follow the official library better. While
here, we also fixed the argument order of the files.

test/enacl_SUITE.erl

@@ -41,7 +41,7 @@ groups() ->
                     [generichash_basic_pos,
                      generichash_chunked,
                      aead_xchacha20poly1305,
-                     aead_chacha20poly1305,
+                     aead_chacha20poly1305_ietf,
                      pwhash,
                      sign,
                      kx]},
@@ -102,16 +102,16 @@ aead_xchacha20poly1305(_Config) ->
     Msg = enacl:aead_xchacha20poly1305_decrypt(Key, Nonce, AD, CipherText),
     ok.
 
-aead_chacha20poly1305(_Config) ->
-    NonceLen = enacl:aead_chacha20poly1305_NPUBBYTES(),
-    KLen = enacl:aead_chacha20poly1305_KEYBYTES(),
+aead_chacha20poly1305_ietf(_Config) ->
+    NonceLen = enacl:aead_chacha20poly1305_ietf_NPUBBYTES(),
+    KLen = enacl:aead_chacha20poly1305_ietf_KEYBYTES(),
     Key = binary:copy(<<"K">>, KLen),
     Msg = <<"test">>,
     AD = <<1,2,3,4,5,6>>,
     Nonce = binary:copy(<<"N">>, NonceLen),
 
-    CipherText = enacl:aead_chacha20poly1305_encrypt(Msg, AD, Nonce, Key),
-    Msg = enacl:aead_chacha20poly1305_decrypt(CipherText, AD, Nonce, Key),
+    CipherText = enacl:aead_chacha20poly1305_ietf_encrypt(Msg, AD, Nonce, Key),
+    Msg = enacl:aead_chacha20poly1305_ietf_decrypt(CipherText, AD, Nonce, Key),
     ok.
 
 pwhash(_Config) ->