Add ability to use business days in metricsql

[dmitry-shur]

Currently both PromQL and MetricsQL are missing search abilities based on business days. Please consider an option to calculate dates based on "business days". Business days should be considered Monday - Friday with Monday as 1st day of week.

[makasim]

@dmitry-shur curious if you could share some real-world use cases? Also, how do you envision the syntax looking like?

[tiny-pangolin]

The real world use cases for adding business days would be things like

• SLIs that only apply on working days, like network uptime in an office
• measuring how often a space is occupied during business days from IoT sensors

[tiny-pangolin]

It would also be helpful if this issue could cover calendar months as well to make things like billing queries simpler

[jiekun]

Similar feature request, for calendar month: https://github.com/VictoriaMetrics/VictoriaMetrics/issues/9685

[dmitry-shur]

Following internal discussions we decided not to move forward with implementation