Add DEPLOY.md: ports, firewall, RPC credentials, SSL, operation

Also fix the COIN default in docs/environment.rst, and refer to the Palladium
node setup by concept instead of by paths of its repository.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

tests/lib/test_palladium.py

@@ -1,4 +1,4 @@
-# Tests of the Palladium coin classes (parameters from palladiumcore src/chainparams.cpp)
+# Tests of the Palladium coin classes (parameters of the Palladium Core chain params)
 
 import pytest