[Feature] Get network name and node from env vars

Description

When running the node using docker-compose, it would be helpful to get the network name and RPC url from environment variables instead of having to modify docker/docker-compose.yml#L22.

This change would do the trick:

diff --git a/docker/docker-compose.yml b/docker/docker-compose.yml
index c78c2eb21..36e8beba7 100644
--- a/docker/docker-compose.yml
+++ b/docker/docker-compose.yml
@@ -19,7 +19,7 @@ services:
       postgres_pass: let-me-in
       postgres_db: graph-node
       ipfs: 'ipfs:5001'
-      ethereum: 'mainnet:http://host.docker.internal:8545'
+      ethereum: ${NETWORK_NAME:-mainnet}:${ETHEREUM_RPC_URL:-http://host.docker.internal:8545}
       GRAPH_LOG: info
   ipfs:
     image: ipfs/kubo:v0.17.0

What do you think?

Are you aware of any blockers that must be resolved before implementing this feature? If so, which? Link to any relevant GitHub issues.

No.

Some information to help us out

• Tick this box if you plan on implementing this feature yourself.
• I have searched the issue tracker to make sure this issue is not a duplicate.

Start with docker/docker-compose.yml at the ethereum configuration around line 22 and review the proposed environment-variable defaults for the network name and RPC URL. Validate the compose configuration and confirm that both variables override their defaults without requiring edits to the file.