Work towards getting RPC tests working again

So much has changed since I originally got the RPC tests working many years ago,
most notably modern Linux distros don't even have a way to install python2 via
packages, you have to install from source. Continuing with python2 does not seem
like a good idea, so we begin migrating thigns to Python 3.

Currently running ./test.sh will successfully spin up a test chain but then
the test suite crashes when attempting to send an RPC request, which looks
to be caused by the test suite internals still expecting python2.

qa/rpc-tests/ac_private.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python2
+#!/usr/bin/env python3
 # Copyright (c) 2016-2024 The Hush developers
 # Copyright (c) 2018 SuperNET developers
 # Distributed under the GPLv3 software license, see the accompanying
@@ -39,13 +39,10 @@ class AssetChainPrivateTest (BitcoinTestFramework):
         self.nodes   = start_nodes(self.num_nodes, self.options.tmpdir,
                     extra_args=[[
                     # always give -ac_name as first extra_arg and port as third
-                    '-ac_name=REGTEST',
-                    '-conf='+self.options.tmpdir+'/node0/REGTEST.conf',
+                    '-ac_name=ZZZ',
+                    '-conf='+self.options.tmpdir+'/node0/ZZZ.conf',
                     '-port=64367',
                     '-rpcport=64368',
-                    '-regtest',
-                    '-addressindex=1',
-                    '-spentindex=1',
                     '-ac_supply=0',
                     '-ac_reward=25600000000',
                     '-ac_private=1',
@@ -78,7 +75,7 @@ class AssetChainPrivateTest (BitcoinTestFramework):
         rpc.getwalletinfo()
 
         taddr = rpc.getnewaddress()
-        print "Sending to " + taddr
+        print("Sending to " + taddr)
         # sending to arbitrary non-notary transparent address is not allowed
         assert_raises(JSONRPCException, rpc.sendtoaddress, taddr,1)