BREAKING CHANGE: WaitForADDomain: Refactored the resource to handle timeout better

[johlju]

Pull Request (PR) description

• Changes to ActiveDirectoryDsc
  • The helper function Find-DomainController is exported in the module
    manifest. When running Import-Module -Name ActiveDirectoryDsc the
    module will also import the nested module ActiveDirectoryDsc.Common.
    It is exported so that the resource WaitForADDomain can reuse code
    when running a background job to search for a domain controller.
  • Changes to ActiveDirectoryDsc.Common:
    • Added function Find-DomainController.
    • Added function Get-CurrentUser (moved from the resource ADKDSKey).
• Changes to WaitForADDomain
  • BREAKING CHANGE: Refactored the resource to handle timeout better and
    more correctly wait for a specific amount of time, and at the same time
    make the resource more intuitive to use. This change has replaced
    parameters in the resource (issue #343).
  • Now the resource can use built-in PsDscRunAsCredential instead of
    specifying the Credential parameter (issue #367).
  • New parameter SiteName can be used to wait for a domain controller
    in a specific site in the domain.

This Pull Request (PR) fixes the following issues

• Fixes WaitForADDomain: Handle timeout better #343
• Fixes WaitForADDomain: Should be able to use PsDscRunAsCredential #367
• Fixes WaitForADDomain: Use helper function Get-ADDirectoryContext #432
• Fixes WaitForADDomain: Integration tests is missing for this resource #360

Task list

• Added an entry under the Unreleased section in the CHANGELOG.md.
  Entry should say what was changed, and how that affects users (if applicable).
• Resource documentation added/updated in resource directory README.md.
• Resource parameter descriptions added/updated in schema.mof
  and comment-based help.
• Comment-based help added/updated.
• Localization strings added/updated in all localization files as appropriate.
• Examples appropriately added/updated.
• Unit tests added/updated. See DSC Resource Testing Guidelines.
• Integration tests added/updated (where possible). See DSC Resource Testing Guidelines.
• New/changed code adheres to DSC Resource Style Guidelines and Best Practices.

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This change is 

[codecov-io]

Codecov Report

Merging #455 into dev will increase coverage by <1%.
The diff coverage is 98%.

@@         Coverage Diff          @@
##            dev   #455    +/-   ##
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+ Coverage    97%    98%   +<1%     
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  Files        20     20            
  Lines      2703   2809   +106     
  Branches     10     10            
====================================
+ Hits       2645   2761   +116     
+ Misses       48     38    -10     
  Partials     10     10

[johlju]

Reviewed 23 of 23 files at r1, 7 of 7 files at r2.
Reviewable status: complete! all files reviewed, all discussions resolved