dockerignore: remove node_modules (#11596)

Cleans up the `.dockerignore` file to no longer ignore `node_modules`
since there is no more JS in the repo. Also ignore `.envrc` to prevent
touching secrets

.dockerignore

 .github
 .vscode
 
-node_modules
-**/node_modules
 .env
+.envrc
 **/.env
 
 test