[Feature Request] Add allowed-times prop in v-time-picker

Problem to solve

The time picker currently supports restricting the input to sets of hours, minutes and seconds via allowed-hours, allowed-minutes, etc. However, it's impossible to restrict allowed input with context of the higher order unit selected, especially in minutes and seconds, thus not allowing to restrict entire times, like the allowed-dates prop does for the date/month pickers.

I'm not talking about restricting selectable times using the min and max properties, but instead working inside a range defined by min and max.

For example, (using 24hr here) let's say we want to allow the user to choose a time between two windows in the 09:00 - 20:00 range: 09:00-11:00 and 14:30-20:00.

• We want the hours selector to allow clicking hours from 09 to 11 and from 14 to 20: this is possibile using allowed-hours alongside min and max.
• We want the minutes selector to do the following:
  • Allow all minutes if the hour is between 09 and 10 or 15 and 19
  • Allow only minute 00 if hour is 11 or 20
  • Allow only minutes 30-59 if hour is 14
  • Allow no minutes if hour is between 00 and 08 or between 21 and 23

Achieving this is currently impossible.: allowed-minutes is unable to to restrict minutes conditionally to the selected hour, since it blindly checks only values from 00 to 59.

Proposed solution

Add an allowed-times prop, which accepts a function which receives a time string (HH:mm:ss) and returns a boolean. allowed-times is context-aware:

type allowedTimesFunction = (val: string) => boolean // val is a string representing time (HH:mm:ss)

Another solution: pass a second parameter to the function used by allowed-minutes and allowed-seconds with the current hour, and a third parameter to allowed-seconds with the current minute:

type allowedMinutesFunction = (minute: number, hour: number) => boolean
type allowedSecondsFunction = (second: number, minute: number, hour: number) => boolean

Start by locating the v-time-picker implementation and reading how allowed-hours, allowed-minutes, allowed-seconds, min, and max interact. Compare the proposed allowed-times API with the alternative callback signatures, then define behavior for the example time windows and verify the selected-hour context is respected.