feat: normalize use of chrono for time and datetime operations

[taddes]

Description

Due to the age of the code and a number of other reasons, we have often “hand crafted” datetime and duration values as integers or strings instead of using well-known constants provided by existing core libraries. In addition, we also tend to use string or u64 representations of times instead of using Instance and Duration values, which can lead to errors and confusion.

This PR aims to make our use more consistent in how we deal with timestamps and time values, favoring chrono yet maintaing std::time::Duration for those APIs like reqwest, deadpool, or actix and expect this in their signatures. We made these updates to Autopush also due to a history of bugs related to inconsistency.

There is mixed use of the time crate, chrono and Rust's standard std::time crate. There are instances in which the signature is maintained, in the example of tokio::time, since it would make needless conversions that complicate the code for no benefit.

The majority of use cases of std::time are related to capturing a duration since epoch, converting to milliseconds and then casting as an i64. Many Duration values remain intact as they are used for type consistency. In instances where Durations are derived and passed into a function, Duration::from_secs() is used, opposed to setting a TimeDelta and converting, which is cumbersome for these use cases.

Crate	Current Role
chrono	Database models, DateTime<Utc>, timestamp formatting, TimeDelta (to be favored as preferential implementation)
std::time	Duration (pool/server timeouts), Instant (metrics), SystemTime/UNIX_EPOCH (timestamp generation)
time	Duration::weeks(52) in syncserver only, therefore removed
tokio::time	Async sleep/timeout — runtime requirement, cannot be replaced

Also fixes an issue with Glean Probe scraper that had the wrong sha.

Issue(s)

Closes STOR-169.