feat: Add option to specify the time of day (BYHOUR, BYMINUTE)

[plammens]

Example:

Output:

RRULE:FREQ=DAILY;INTERVAL=1;UNTIL=20231211;BYHOUR=16;BYMINUTE=0;EXDATE=20240322T000000

[tkortekaas]

Hey @plammens thanks a lot for the PR. I think this would be a good addition to the package. The rrule package for instance does support by hour and by minute. However, I would propose to make it possible to add multiple byHours and multiple byMinute's. Right now, as far as I can tell, it is only possible to add a single byHour and byMinute.
I had a look at this comment by the rrule package author about how he handles byMinute and byHour and there is some more complexity as we would also want to support bySetPos.
If we start providing support for byMinute and byHour, I would want to provide full support, so also provide support for the this rule, as copied from the rrule author's comment:
RRULE:FREQ=DAILY;INTERVAL=2;WKST=MO;BYSETPOS=1,5,9;BYHOUR=3,16,21;BYMINUTE=15,0,15

[plammens]

Yes indeed, this for now was just a quick addition for my use case and it supports only a single BYHOUR and BYMINUTE. I agree it would be good to provide full support of the rrule specification, I'll see if I can get round to it sooner or later.