Put all the rendering functions into their own module

src/output/mod.rs

@@ -16,7 +16,4 @@ mod colours;
 mod tree;
 pub mod file_name;
 mod escape;
-mod users;
-mod groups;
-mod permissions;
-mod size;
+mod render;

src/output/render/mod.rs

@@ -0,0 +1,4 @@
+mod groups;
+mod permissions;
+mod size;
+mod users;