Always update connections.env and fix double-toggled connection line

Drop the --legacy flag: set_local_db and toggle_index now run
unconditionally instead of only when -l was passed, since that was the
flag's only effect.

Fix set_dot_env writing the connection/RCC_CONNECTION line twice with
opposing polarity (once from the #docker pass, once from the #cidb
pass), which flipped it to the wrong value. Collapsed the three
separate open/read/write passes into one, toggling both sections and
the connection line in a single scan so the connection line is only
ever touched once.

src/main.rs

@@ -22,14 +22,9 @@ fn main() -> Result<()> {
     let start: bool = args.action == "up";
 
     start_docker_compose(&config.container_service, &config.container_dir, start)?;
-    if args.legacy {
-        println!("[!] Legacy mode active.");
-        print!("{}", set_local_db(start, &config)?);
-        toggle_index(start, &config)?;
-    } else {
-        println!("[!] Legacy mode deactivated.");
-    }
 
+    print!("{}", set_local_db(start, &config)?);
+    toggle_index(start, &config)?;
     print!("{}", set_dot_env(start, &config)?);
 
     println!(