Allow skipping the colon when parsing time

[Gelio]

Sometimes the colon is unnecessary when resolving the time.

• 725 -> 7:25
• 1420 -> 14:20
• 5 -> 5:00

Let's modify the time parser to account for these situations.

Sometimes this could lead to ambiguities:

• Oct 2 725 -> 725-10-2 (just the date) or 2023-10-02 7:25

I believe we should only make the colon optional when the format expects a time, so:

• after a relative date
• after a day of the week
• at the beginning of the query