feat: allow docker compose overrides

- use file override to handle multiple networks
- expose and map only required ports
- name containers differently
- add environment for chain variable
- dont expose ports in image
Signed-off-by: Lakshya Singh <lakshay.singh1108@gmail.com>

docker-compose.regtest.yml

@@ -0,0 +1,25 @@
+version: "3.8"
+name: regtest
+services:
+  bitcoin-core:
+    container_name: bitcoind-regtest
+    expose:
+      - 38332
+    ports:
+      - 38333:38333
+    environment:
+      - BITCOIN_CHAIN=regtest
+
+  core-lightning:
+    container_name: lightningd-regtest
+    command:
+      - --conf=/home/lightning/.lightning/regtest-config
+      - --bitcoin-rpcconnect=bitcoind
+    expose:
+      - 19846
+    ports:
+      - 19846:19846
+    env_file:
+      - ./assets/regtest-env
+    environment:
+      - BITCOIN_CHAIN=regtest