Improve time conversion helpers

[taldcroft]

Description

This improves the time conversion helper utilities which are available as a CLI via the cxotime script or the print_conversions() method of CxoTime.

• Factor out the conversions bit into a new get_conversions() method.
• Add parameters to methods that allow for unit testing.
• CLI script was put into a more standard place in scripts, now being run through main().
• Conversion to local time is now done using timezone support in a built-in module available in Python 3.10.
  • Unlike the previous method, this gives the expected local time zone even after django.setup() is run if the TZ environment var is removed.

Interface impacts

None

Testing

Unit tests

• Mac (new unit tests)

Functional tests

In [1]: import kadi.events

In [2]: kadi.events.eclipses
Out[2]: <EventQuery: Eclipse>

In [3]: import os

In [4]: os.environ["TZ"]
Out[4]: 'America/Chicago'

In [5]: del os.environ["TZ"]

In [6]: from cxotime import CxoTime

In [7]: CxoTime("2022:300:01:00:00.000").get_conversions()
Out[7]: 
{'local': '2022 Wed Oct 26 09:00:00 PM EDT',
 'iso_local': '2022-10-26T21:00:00-04:00',
 'date': '2022:300:01:00:00.000',
 'cxcsec': 783219669.184,
 'decimalyear': 2022.8192922374428,
 'iso': '2022-10-27 01:00:00.000',
 'unix': 1666832400.0}

In [8]: os.environ["TZ"] = "America/Chicago"

In [9]: CxoTime("2022:300:01:00:00.000").get_conversions()
Out[9]:
{'local': '2022 Wed Oct 26 08:00:00 PM CDT',
'iso_local': '2022-10-26T20:00:00-05:00',
'date': '2022:300:01:00:00.000',
'cxcsec': 783219669.184,
'decimalyear': 2022.8192922374428,
'iso': '2022-10-27 01:00:00.000',
'unix': 1666832400.0}

[jeanconn]

The new 'scripts' dir needs to be added to the setup.py 'packages' set.

[jeanconn]

No biggie, but I naively tried "cxotime --help" and "cxotime -help" and they weren't helpful as that just throws an exception ValueError: Input values did not match any of the formats where the format keyword is optional...

So I'm not sure if there is some value to supporting some kind of usage help.

[jeanconn]

Works for me now.