feat: exec mode improvements

Use Bollard library to exec in pure Rust.

`--use-cli` cli arg, will then only try to exec into containers using
Docker.

Only try to exec into a container if the state == Running.

src/docker_data/message.rs

@@ -1,9 +1,14 @@
-use crate::app_data::ContainerId;
+use std::sync::Arc;
 
-#[derive(Debug, Clone)]
+use crate::app_data::ContainerId;
+use bollard::Docker;
+use tokio::sync::oneshot::Sender;
+
+#[derive(Debug)]
 pub enum DockerMessage {
-    Delete(ContainerId),
     ConfirmDelete(ContainerId),
+    Delete(ContainerId),
+    Exec(Sender<Arc<Docker>>),
     Pause(ContainerId),
     Quit,
     Restart(ContainerId),