Allowe duration based entries

[3Fish]

I think often you have elements where you're roughly how long they will take, but not when you will be able to do them.
I would like to have the day planer consider the order of tasks and just insert a block of the given duration after the previous task. If the previous task has an end time, it should be directly after it; otherwise it should be moved as the time progresses, but stops moving back when it collides with the next fixed task. Multiple duration tasks would then just move together.
If a previous open end task is marked as done, the completion time is used as the end date for the purpose of moving the duration-based tasks.

The format could be something like ~15 for minutes and ~2:30 for hours and minutes.

- [ ] 09:15 - 10:00 Read emails
- [ ] ~15 Get a Coffee
- [ ] 12:00 Meeting with Customer
- [ ] ~1:00 Get lunch
- [ ] 17:00 Pick up the Kids

it is before 12 o'clock

it is 13 o'clock

any time after 16 o'clock

the customer meeting was done at 14 o'clock

[GroveTomas]

Totally support this feature request!
I found the day planner just because I bumped into this plugin for roam research Nautilus in one of my newsletters.
Love the idea. But I have no idea how hard it is to implement.