refactor: Remove ApiVersion from normal DTOs except EventDTO

[weichou1229]

Close #537

PR Checklist

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• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

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What is the current behavior?

The apiVersion is required.

Issue Number: #537

What is the new behavior?

• Remove the required validation tag from apiVersion.
• Check the requestDTOs and EventDTO which should contains valid api version

Does this PR introduce a breaking change?

• Yes
• No

New Imports

• Yes
• No

Specific Instructions

Are there any specific instructions or things that should be known prior to reviewing?

Other information

[weichou1229]

I tried to write a custom tag to verify the DTO which should contain api version like:

type BaseRequest struct {
	Versionable  `json:",inline" validate:"edgex-dto-api-version-required"`
	RequestId     string `json:"requestId" validate:"len=0|uuid"`
}

But it didn't work because the validation lib ignore the embedded struct's tag. So I check the apiVersion in the Validation function.

[codecov-io]

Codecov Report

Merging #538 (581db9a) into master (2e84a19) will increase coverage by 0.07%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #538      +/-   ##
==========================================
+ Coverage   55.79%   55.87%   +0.07%     
==========================================
  Files         119      119              
  Lines        3570     3551      -19     
==========================================
- Hits         1992     1984       -8     
+ Misses       1385     1374      -11     
  Partials      193      193              

Impacted Files	Coverage Δ
v2/dtos/device.go	8.19% <ø> (+0.13%)	⬆️
v2/dtos/deviceservice.go	12.12% <ø> (+0.35%)	⬆️
v2/dtos/interval.go	0.00% <ø> (ø)
v2/dtos/intervalaction.go	0.00% <ø> (ø)
v2/dtos/provisionwatcher.go	15.00% <ø> (+0.36%)	⬆️
v2/dtos/requests/device.go	89.28% <ø> (-0.19%)	⬇️
v2/dtos/requests/deviceprofile.go	83.33% <ø> (-0.67%)	⬇️
v2/dtos/requests/deviceservice.go	94.73% <ø> (-0.14%)	⬇️
v2/dtos/requests/interval.go	72.50% <ø> (+1.76%)	⬆️
v2/dtos/requests/intervalaction.go	82.97% <ø> (-0.36%)	⬇️
... and 6 more

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[lenny-goodell]

LGTM