Add API support for Time Tracking

Description

In 8.14 we will ship Time Tracking as a Product. We won't have an API for that.

The sooner we have APIs for this Product, the faster we'll see integrations that take advantage of it (IDEs, other SAAS, or companies that build custom reports as they do now with all other features we have).

Proposal

• Add new API methods for time tracking:

  • Read: total time spent for an issue/MR
  • Write: individual time spent for an issue/MR (add up to previous entries)
  • Read: estimate for an issue/MR
  • Write: estimate for an issue/MR (overwrite previous entries)

• This API has to be restricted to EE Premium.

Out of scope:

• Read: list of individual time spent entries per issue/MR

/cc @smcgivern

@rdavila you've been working on this, so you'll have a better idea than me Is there a natural API design for this you can think of?

Mentioned in issue #1293

mentioned in issue #1271 (closed)

changed title from Add new API for Time Tracking to Add API support for Time Tracking

@rdavila can we do this in 8.16 in one shot?

@regisF I think so, I'll give a detailed look and will list the possible API endpoints here.

assigned to @rdavila

This would be awesome I'll be the first one to use theese api methods

Proposal

I think another possible read feature could be: is_overtime or something like time_percent with the intent to read if the issue time tracking is "red" or not. This would be just a plus, i know it is calculable with reading data.

@paolofalomo in which context would you be using those API methods?

mentioned in issue #1415

@regisF @rdavila we'll integrate this in https://hubstaff.com/ to our current GitLab integration as soon as it's ready.

@regisF please move to CE and include the move to CE for basic time tracking.

moved to gitlab-org/gitlab-ce#25861

added Stretch label

changed milestone to %8.16