Include Encoding objects/HasEncoding references

[VasilBK]

This is a prerequisite for the AML → NodesetXML conversion.

Currently, Encoding Objects (Default JSON/XML/Binary) and their corresponding HasEncoding references are treated as overhead and are not included in the conversion.

This leads to incomplete NodesetXML output and breaks round-trip consistency.

[JimLuth]

See corresponding spec issue https://mantis.opcfoundation.org/view.php?id=10890

[JimLuth]

When a new structure is defined in a Nodeset, in addition to the Node created for the structure itself, a second Node is defined and assigned a NodeId -- this is the DefaultEncodingId for that newly defined structure. There is no additional metadata for the DefaultEncoding Node so the only value assigned is the NodeId for this empty Node.

When a NodeSet is read into the DotNet library (used be the AML Converter code), the DefalultEncodingId for each defined structure is included in the DotNet object for that structure (according to Randy). The ALM Converter simply needs to included this NodeId in the AML structure definition in the AttributeTypeLibrary.