WebConfigPropertyCollection - allow different property collection key types to be added, IisModule / IisMimeTypeMapping - set Ensure as default

[Borgquite]

Pull Request (PR) description

• Allow WebConfigPropertyCollection to be used to add different key types when there are none already (e.g. to allow https://stackoverflow.com/questions/30135330/managing-iis-net-authorization-rules-with-a-powershell-script)
• Set IisModule, IisMimeTypeMapping to have Ensure = 'Present' by default.

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).
• [x] 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.
• [x] Unit tests added/updated. See DSC Community Testing Guidelines.
• [ ] Integration tests added/updated (where possible). See DSC Community Testing Guidelines.
• [ ] New/changed code adheres to DSC Community Style Guidelines.

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This change is 

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 88%. Comparing base (da0cd60) to head (808f7cf). Report is 6 commits behind head on main.

Additional details and impacted files

@@         Coverage Diff         @@
##           main   #640   +/-   ##
===================================
  Coverage    88%    88%           
===================================
  Files        15     15           
  Lines      1952   1952           
===================================
  Hits       1726   1726           
  Misses      226    226           

Files with missing lines	Coverage Δ
...DSC_IisMimeTypeMapping/DSC_IisMimeTypeMapping.psm1	100% <ø> (ø)
...urce/DSCResources/DSC_IisModule/DSC_IisModule.psm1	0% <ø> (ø)
...rtyCollection/DSC_WebConfigPropertyCollection.psm1	98% <ø> (ø)

[dan-hughes]

@johlju

[Borgquite]

As always @dan-hughes , @johlju - thank you! :)