Pubsub JSON updates preview

[mregen]

Proposed changes

Add support for new Compact and Verbose JSON encodings.

Other bug fixes:

• Defaults for non reversible forces the namespace Uri in the NodeId encoding and all default values are encoded. This behavior is according to spec. Old behavior can be changed reestablished with properties on creation of the JSON encoders.
• Compact and Verbose are preview for the next spec release. Main difference is to always encode NodeIds and ExpandedNodeIds as string with NamespaceUri. Same for QualifiedName. Both are considered reversible encodings.
• JSON decoder accepts any of the new and existing JSOn encodings no matter if the NodeId are encoded as string or JSON object.

Related Issues

• Fixes #

Types of changes

What types of changes does your code introduce? Put an x in the boxes that apply. You can also fill these out after creating the PR.

• [ ] Bugfix (non-breaking change which fixes an issue)
• [x] Enhancement (non-breaking change which adds functionality)
• [ ] Test enhancement (non-breaking change to increase test coverage)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected, requires version increase of Nuget packages)
• [ ] Documentation Update (if none of the other choices apply)

Checklist

Put an x in the boxes that apply. You can also fill these out after creating the PR. If you're unsure about any of them, don't hesitate to ask. We're here to help! This is simply a reminder of what we are going to look for before merging your code.

• [x] I have read the CONTRIBUTING doc.
• [x] I have signed the CLA.
• [ ] I ran tests locally with my changes, all passed.
• [ ] I fixed all failing tests in the CI pipelines.
• [ ] I fixed all introduced issues with CodeQL and LGTM.
• [ ] I have added tests that prove my fix is effective or that my feature works and increased code coverage.
• [ ] I have added necessary documentation (if appropriate).
• [ ] Any dependent changes have been merged and published in downstream modules.

Further comments

If this is a relatively large or complex change, kick off the discussion by explaining why you chose the solution you did and what alternatives you considered, etc...

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
3 out of 4 committers have signed the CLA.

:white_check_mark: randy-armstrong
:white_check_mark: mregen
:white_check_mark: mrsuciu
:x: Randy Armstrong

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[codecov[bot]]

Codecov Report

Attention: Patch coverage is 66.81319% with 151 lines in your changes missing coverage. Please review.

Project coverage is 54.76%. Comparing base (cf2e788) to head (9b0e747). Report is 5 commits behind head on master.

Files with missing lines	Patch %	Lines
Stack/Opc.Ua.Core/Types/Encoders/JsonDecoder.cs	66.92%	20 Missing and 22 partials :warning:
Stack/Opc.Ua.Core/Types/BuiltIn/NodeId.cs	55.00%	24 Missing and 12 partials :warning:
Stack/Opc.Ua.Core/Types/BuiltIn/ExpandedNodeId.cs	58.10%	22 Missing and 9 partials :warning:
Stack/Opc.Ua.Core/Types/BuiltIn/QualifiedName.cs	47.22%	11 Missing and 8 partials :warning:
Stack/Opc.Ua.Core/Types/Encoders/JsonEncoder.cs	87.28%	14 Missing and 1 partial :warning:
Stack/Opc.Ua.Core/Types/Utils/Utils.cs	57.89%	5 Missing and 3 partials :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #2768 +/- ## ========================================== - Coverage 55.04% 54.76% -0.28% ========================================== Files 349 349 Lines 65697 66018 +321 Branches 13441 13542 +101 ========================================== - Hits 36162 36157 -5 - Misses 25688 25937 +249 - Partials 3847 3924 +77 ```

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[mregen]

@mrsuciu @NoahHoelterhoff I checked your concern but I think the implementation is ok as is.