feat!: respect COMPOSE_FILE env and remove docker command

Read COMPOSE_FILE from env and use it if it is set. Default is still
docker/local/docker-compose.yaml.

BREAKING CHANGE: Removed docker subcommand. Added deprecation notice to
compose subcommand.

src/cli/ahab.rs

@@ -1,4 +1,4 @@
-use super::{Django, Docker, DockerCompose, Postgres};
+use super::{Django, DockerCompose, Postgres};
 use clap::{Parser, Subcommand};
 
 /// A program for interacting with various dockerized applications.
@@ -11,12 +11,6 @@ pub struct Ahab {
 
 #[derive(Debug, Subcommand)]
 pub enum Commands {
-    /// Docker related subcommands
-    Docker {
-        #[command(subcommand)]
-        command: Docker,
-    },
-
     /// Docker compose related subcommands
     Compose {
         #[command(subcommand)]