Time-decode

CHANGELOG
This version introduces new timestamps and fixes, as well as new features for the GUI:

Fixes
- Active Directory conversion would fail when the timestamp value is negative or larger than the year 3001
- Converting from an NS Date value would present 4 outputs instead of a single output

New Timestamps
- Julian Decimal date
- Julian Hex date
- Semi-Octet decimal value
- Unix Milliseconds (hex)

Updates
- Added a time zone conversion feature to the GUI (one already existed for the command line version)
- Created a "Open in New Window" function for side-by-side comparison of timestamps
- Added a context menu in the results tables for copying / pasting values
- Added an "Update time zone" button in the calendar to facilitate updating the time zone lists to respect daylight savings
- Modified the output tables to detect a +/- 5 year difference and change the color of the row to green
- Changed the sizing of the windows, and modified the fonts to allow for a more user-friendly view in Linux

This release adds the LEB128 timestamp and the Apache Cookie timestamp.
It also adjusts the errant tab on the S32 timestamp output.

This version fixes some graphical issues where resolution is not advanced enough to handle the size of the output window, or the Examples window.

Updates
- Added a GUI (time-decode -g)
- New GUI means change in requirements (added PyQt6)
- Fixed some issues with iOS time conversion
- Moved the references in the script itself out of the script and into REFERENCES.md
- Generated a standalone executable for the GUI as well (available under Releases)

Fixed a couple of minor errors where calls were made to variables prior to referencing.

Major overhaul of script design to enable import of time_decode as a module.
Added the Biome 64-bit decimal timestamp, and S32-Encoded timestamp as new options.

More instructions to follow for usage of time_decode as a module.