worldclock script and addition to .env-template

[glutenfreepy]

Hi Bob! This PR adds a worldclock tool to the repo that looks like this:

I still need to write the doc for it, but it's pretty simple: You input your desired timezones in a list in the .env file...and that's it!

Future improvements could be things like these:

• using a friendly name in place of the formal timezone's name
• adding the option to display the date after the time

Please let me know what you think!

Thank you, Ed