Replace i64 with DateTime

[fqaiser94]

Fixes: #90

First time contributor to this repo.
Extremely new to rust (not new to iceberg, used it extensively and contributed a couple of small things there).

How is this for an approach?
I used chrono::DateTime<Utc> but had to wrap it in a NewType to implement the Serialize and Deserialize traits (as otherwise we run into Rust's orphan rule issue).

[fqaiser94]

Moving back to draft while i address comments. Will ping when it's ready again, shouldn't take too long!

[liurenjie1024]

Thanks for this pr. I've left some comments.

[Xuanwo]

LGTM, great work!

[liurenjie1024]

LGTM, thanks!

[fqaiser94]

Is there anything else I need to do to get this merged in?

I don't (understandably) have permissions to merge this myself.

[liurenjie1024]

Is there anything else I need to do to get this merged in?

I don't (understandably) have permissions to merge this myself.

cc @Fokko PTAL

[Fokko]

Looks like we have a sad clippy:

error: argument to `panic!()` in a const context must have type `&str`
   --> crates/catalog/rest/src/catalog.rs:985:13
    |
985 |             uuid!("b55d9dda-6561-423a-8bfc-787980ce421f"),
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `uuid` (in Nightly builds, run with -Z macro-backtrace for more info)

[liurenjie1024]

The failure is caused by upgrades of uuid. You can solve it by fixing version as this pr:

cc @fqaiser94

[liurenjie1024]

cc @Fokko Any other comments?

[Fokko]

Thanks @fqaiser94 for the PR, and @liurenjie1024 & @Xuanwo for the review 🙌