Make it easier to set a time estimation
With the increased importance of time estimates when we introduce ~"Portfolio Management" we should strive for not hiding the time estimation functionality in purely slash/quick commands, it is currently a bit hidden like that.
Introduce a way to set it from the GUI, similar to due dates.
Time estimates may become equally important to upper management with the introduction of ~"Portfolio Management" and maybe an alternative to using weights to indicate work needed. Therefore time estimates could use a similar treatment to https://gitlab.com/gitlab-org/gitlab-ee/issues/3403 which introduces an automated prefill of this field.