Example of headers created by Stalwart below
X-Spam-Result: TRUSTED_DOMAIN (-7.00),
PROB_HAM_LOW (-2.00),
RBL_SENDERSCORE_REPUT_9 (-1.00),
DMARC_POLICY_ALLOW (-0.50),
RCVD_DKIM_ARC_DNSWL_MED (-0.50)
X-Spam-Score: ham, score=-5.60, avg_confidence=0.26
X-Spam-Status: No
Only need to add small tweak by detecting spam|ham as well as Yes|No
The most useful header is X-Spam-Score, so we make sure to parse that
before X-Spam-Status
