Specifying a start of metadata generation which is not a date but a datetime

[cparcerisas]

Hi,
when I specify the start argument for the creation of a SoundTrapMetadataGenerator which is NOT a date but a datetime (let's say 11 AM of a random day) at a specific hour, the metadata generated is then not split per natural day but from 11 AM to 11 AM of the next day.
This then creates that the generated nc files are only full from 11 AM to the end of the day - and the rest of the data is ignored.

So, I propose two possible solutions for this:

1. Raise an error when the param is not a date but a datetime so the user is aware of this and can change it
2. Add a rounding in the metadata generator where start is converted to its date

What do you think?
I am happy to implement whatever of the two options you decide :)

[danellecline]

@cparcerisas my preference is option 1. 😄 Thanks for the contribution!

If you could add any details to the documentation on the expected format and behavior, that would be terrific too here: https://github.com/mbari-org/pbp/blob/main/pbp-doc/docs/pbp-meta-gen/index.md