Add and connect "list-packages" subcommand

And with that I have the API call being made!... except it doesn't work
quite right.

src/cli.rs

@@ -44,4 +44,5 @@ pub enum Commands {
         #[arg()]
         files: Vec<String>,
     },
+    ListPackages,
 }

src/main.rs

@@ -134,6 +134,16 @@ async fn main() -> Result<(), gt_tool::Error> {
                 return Err(gt_tool::Error::NoSuchRelease);
             }
         }
+        gt_tool::cli::Commands::ListPackages => {
+            let packages = gt_tool::api::packages::list_packages(&client, &gitea_url, &owner, None).await?;
+            itertools::Itertools::intersperse(
+                packages
+                    .iter()
+                    .rev()
+                    .map(|pkg| pkg.colorized()),
+                String::from("")
+            ).for_each(|package| println!("{package}"));
+        }
     }
 
     Ok(())