feat: change timeout type from int to time.Duration

[mursisoy]

If your build fails due to your commit message not passing the build checks, please review the guidelines here: https://github.com/edgexfoundry/device-modbus-go/blob/main/.github/Contributing.md

PR Checklist

Please check if your PR fulfills the following requirements:

• I am not introducing a breaking change (if you are, flag in conventional commit message with BREAKING CHANGE: describing the break)
• I am not introducing a new dependency (add notes below if you are)
• I have added unit tests for the new feature or bug fix (if not, why?)
• I have fully tested (add details below) this the new feature or bug fix (if not, why?)
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Testing Instructions

Add a device profile with Timeout and IdleTimeot with valid strings as stated here: https://pkg.go.dev/time#ParseDuration

New Dependency Instructions (If applicable)

[cloudxxx8]

It's a good idea to use ISO 8601 string to represent the timeout format. However, this is a breaking change. This would break all the existing users with this protocol property. This change needs to be held until 3.0
Also, please follow the contribution guide to open the issue, describe the reason, proper commit message, and DCO.
https://wiki.edgexfoundry.org/display/FA/Committing+Code+Guidelines

[lenny-goodell]

@cloudxxx8 , looks like this missed the 3.0 release? Should put it on the list for 4.0?
https://github.com/orgs/edgexfoundry/projects/64

[cloudxxx8]

ok, I just added it to the board