issue #9: combine spreadsheet timesheet and calendar sync code

[rngadam]

see: https://youtu.be/laRRpfWbYKM

[sam123evers]

Do I need to paste the code from TimesheetSync into a new script from internal timesheet? (< > script editor)?

When I look at add-ons for the internal timesheet, I only see this:

When I do test TimesheetSync as an add-on, my only option is "snapshot timesheet"

[rngadam]

I changed the menu string to make easier to validate and tested both under my gmail address and coderbunker address: