chrono deprecations warning cleanup

[yeastplume]

Cleans up warnings related to specific errors, mostly from_timestamp moving to a from_timestamp_opt function that returns an options.

Note from_timestamp_opt returns None in the following circumstances:

Returns None on the out-of-range number of seconds (more than 262 000 years away from common era) and/or invalid nanosecond (2 seconds or more).

• Where timestamps are hardcoded on initialization (such as being hardcoded with 0s), I've just called unwrap as there's no reason for the function to return None
• Where timestamps are initialized dynamically in critical code check for None and return appropriate error
• where timestamps are less crucial, (tui, mining) just unwrap_or_default

[yeastplume]

6 Month re-review: think all of these are fine. PIBD is released and master set to an alpha so good time to integrate these.