Allow for Relative Dates in Time/Date fields

What is a one sentence summary of your feature request?

Allow for Relative Dates in Time/Date fields in all areas

Please describe your idea in detail. What is your problem, why do you feel this idea is the best solution, etc.

When performing an investigation, setting up an alert or subscription, etc. it would be very convenient to be able to select a relative date in addition to a date range, such as:
-Yesterday
-Last Week
-Last Month
-Past ## days

How do you currently solve the challenges you have by not having this feature?

Set the date(s) manually