Support day unit in ValidateDuration validation function

[lindseysimple]

🚀 Feature Request

Relevant Package [REQUIRED]

This feature request affects to all DTO fields with the edgex-dto-duration validation tag

Description [REQUIRED]

The ValidateDuration function, which is registered under the edgex-dto-duration validation tag, currently supports only the following time units: "ns" (nanoseconds), "us" or "µs" (microseconds), "ms" (milliseconds), "s" (seconds), "m" (minutes), and "h" (hours), consistent with Go's time.ParseDuration() behavior.

However, the "d" (days) unit is commonly used in certain contexts—such as retention policy configurations—and would be a valuable addition to the set of supported duration units.

Describe the solution you'd like

Enhance the ValidateDuration validation function to support the "d" (days) time unit.