Remove boltz service and RTL integration

We use peerswap these days, and the build process for boltz was made
much more complicated at some point. Not worth upgrading for us.

nodes/bitcoin-2.json

@@ -33,7 +33,6 @@
       "kosmos-bitcoin::c-lightning",
       "kosmos-bitcoin::lnd",
       "kosmos-bitcoin::lnd-scb-s3",
-      "kosmos-bitcoin::boltz",
       "kosmos-bitcoin::rtl",
       "kosmos-bitcoin::peerswap-lnd",
       "kosmos_postgresql::hostsfile",