[sw, dif] Introduce AES smoke test

This change introduces an AES smoke test that is refactored copy
of `sw/device/tests/aes_test.c` to use `dif_aes`. The original test
has not been removed (should be done by the SCA/HW team) in case
there is need to compare performance between two, etc...

Due to C strict aliasing u8 pointers cannot be freely cast into u32
pointers, which makes the API somewhat cumbersome to use (see
`in_data`, `out_data` and `key_share` packing through memcpy).

Signed-off-by: Silvestrs Timofejevs <silvestrst@lowrisc.org>
diff --git a/test/systemtest/config.py b/test/systemtest/config.py
index b63a7ef..065a8a4 100644
--- a/test/systemtest/config.py
+++ b/test/systemtest/config.py
@@ -42,6 +42,9 @@
         "targets": ["fpga_nexysvideo"],
     },
     {
+        "name": "dif_aes_smoketest",
+    },
+    {
         "name": "dif_otp_ctrl_smoketest",
     },
     {