Return local date on session endpoints.

[jolpica]

Currently we return a UTC date & time for sessions.

This isn't ideal as cases such as the 2025 las vegas grand prix can have a different date locally vs utc (see #158).
This is counter intuitive for consumers as it can appear that qualifying occurs on Sunday instead of Saturday.

Ideally in a new endpoint we should get rid of UTC date, and use a UTC timestamp alongside a local date.