Gantt project should use business calendar by default

[arcady-zherdev]

That will repeat what MS Project does by default so we'll avoid typical "how to make it look like ms project" questions.

Yet just changing the project calendar is not enough.
MS Project also displays tasks so their start snap to tick left borders (and finish dates snap to right borders respectively). This happens only when tick sizes >= a day IIRC.
And the Gantt currently doesn't support that.

So two things need to be done here:

• Implement tasks snapping to tick borders
• Change default calendar of the Gantt project to 8hrs/day

[arcady-zherdev]

fillTicks POC was pushed to the advanced demo in 2475-project-calendar-and-fill-ticks branch

[arcady-zherdev]

MS Project seems uses non-continuous time axis (08:00-17:00) by default. So they don't stretch bars. Tasks scheduled between ticks are displayed with some minimum width there.