DnsServerDsc: Align some class-based resources with new pattern

[johlju]

Pull Request (PR) description

• ResourceBase
  • For the method Get() the overload that took a [Microsoft.Management.Infrastructure.CimInstance] was removed as it is not the correct pattern going forward.
  • Added new method Assert() tha calls Assert-Module and AssertProperties().
  • Moved the Assert-Module from the constructor to a new method Assert() that is called from Get(), Test(), and Set(). The method Assert() also calls the method AssertProperties(). The method Assert() is not meant to be overridden, but can if there is a reason not to run Assert-Module and or AssertProperties().
• DnsServerCache
  • Moved to the same coding pattern as DnsServerRecursion.
• DnsServerEDns
  • Moved to the same coding pattern as DnsServerRecursion.
• DnsServerScavenging
  • Moved to the same coding pattern as DnsServerRecursion.

This Pull Request (PR) fixes the following issues

None.

Task list

• [x] Added an entry to the change log under the Unreleased section of the file CHANGELOG.md. Entry should say what was changed and how that affects users (if applicable), and reference the issue being resolved (if applicable).
• [ ] Resource documentation added/updated in README.md.
• [ ] Resource parameter descriptions added/updated in README.md, 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 Community Testing Guidelines.
• [ ] Integration tests added/updated (where possible). See DSC Community Testing Guidelines.
• [x] New/changed code adheres to DSC Community Style Guidelines.

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This change is 

[codecov[bot]]

Codecov Report

Merging #247 (4e86a8b) into main (a2eedd1) will decrease coverage by 0%. The diff coverage is n/a.

@@         Coverage Diff         @@
##           main   #247   +/-   ##
===================================
- Coverage    90%    90%   -1%     
===================================
  Files        14     14           
  Lines      1514   1476   -38     
===================================
- Hits       1375   1337   -38     
  Misses      139    139           

Impacted Files	Coverage Δ
source/DnsServerDsc.psm1	99% <0%> (-1%)	:arrow_down:

[johlju]

Merging this to remove old behavior from the base class so it is easier to go forward in subsequent PR's.