Switch to time crate, add file sizes (#329)

* Switch to time crate, add file sizes

* Update deps, adjust pack format

* Run formatter, fix clippy

src/util/mod.rs

@@ -3,5 +3,6 @@ pub mod env;
 pub mod ext;
 pub mod guards;
 pub mod routes;
+pub mod time_ser;
 pub mod validate;
 pub mod webhook;