Fix date format to save PM time

[fsidobre]

Hello!
The recent changes to the format handled by date & datetime fields introduced a few bugs :

Having the h format instead of H for hour will :

• make default hour stored for date fields as 12:00
• make default hour for query comparison as 12:00 (e.g. when using where { date: '>yesterday' })
• only store the hour in a range between 0 and 12 on a datetime field when you type a PM hour (with or without the AM/PM selector)

Fixes #3024

[Joossensei]

Looks good! And nice that you wrote some tests for these as well!

[bobdenotter]

Thanks @fsidobre 👍

The failures in the CI are fixed in #3053