Add LBTC and USDT support; (#240)

* Add LBTC and USDT support;

Requires:
https://github.com/btcpayserver/btcpayserver/pull/1118
https://github.com/dgarage/NBXplorer/pull/198
https://github.com/btcpayserver/dockerfile-deps/pull/10

* add elementsd cli scripts

* simplify liquid integration

btcpay liquid PR adds all sub assets in one go so in docker specifying LBTC is enough

* bump images

* rename properly

* fix rpc

* add pruning for liquid node

* bump nbx

* add liquid more-memory

docker-compose-generator/docker-fragments/opt-more-memory.yml

@@ -30,5 +30,9 @@ services:
     environment:
       BITCOIN_EXTRA_ARGS: |
         dbcache=1024
+  elementsd_liquid:
+    environment:
+      ELEMENTS_EXTRA_ARGS: |
+        dbcache=1024
 exclusive:
   - memory