Use Instant for modeling timestamps

[armanbilge]

AKA how do we feel about a scala-java-time dependency.

Pros:

• Instant is most idiomatic representation of a timestamp

Cons:

• Bloats generated JS

Mitigation:

• Estimated to be a 120 kb dependency in Reduce the impact of MimeDB on JS size http4s/http4s-dom#30 (comment)
• JS size is not as a big a deal for Node.js lambda compared to browser.
• skunk and http4s already bring in this dependency anyway.

[bpholt]

I lean towards using Instant and including the dependency. 120kb doesn't seem like a big deal for this purpose and having the idiomatic representation will be less confusing for users.

[kubukoz]

120kb doesn't seem like much in the scale of 50megs (aws limit)

[armanbilge]

Cool, I'd say that's decided :) anyone feel free to PR an update to events with this.