Provide support for Custom Field

I've provided a start to support for Time
But not sure how to add the correct constraints in the TimeType... So will need help there.
See https://git.drupalcode.org/project/time_field/-/merge_requests/16/diffs#...

If this is a good proposal, we can implement this for TimeRangeType also.

There is some duplicate code that can be substracted to a service or helper class. This can be discussed.

I have no objections for adding this :-) setting back for the other widget and the todo in the code.

• The empty value (86401) was missing. I've introduced a static function to check for this.
• Constraint check added too.
• Rebase with current 2.x

There more potential for reuse of code parts.
Also, the empty value 86401 appears both as int and string across the module. I recommend streamlining this.