Decimal time format

Add ability to record time as a hours-decimal format as alternative option to hours-minutes format. Hourly billing rates are confusing when not expressed in hours, e.g., 1:30 is confusing clients as 1.3 hours rather than 1.5 hours, putting invoice accuracy into question.

(note: added comment to a similar topic - Changing hours data entry such that 1 defaults to 1 hr} - so as to not get lost as a distinct feature request, creating specific topic / thank you)