Working user and link list, (big)restructure

This is now a workspace consisting of:
  * the pslink app (a wasm frontend for the admin interface)
  * the pslink binary
  * shared - modules for communication between the two above.

app/src/pages/mod.rs

@@ -0,0 +1,3 @@
+pub mod home;
+pub mod list_links;
+pub mod list_users;