feat: Handle XMLLiteral Java type

[berezovskyi]

Description

Lyo uses XMLLiteral type for XML Literals in RDF when creating extended properties but uses String type for annotated Java properties for the same RDF type. This caused differences in processing of the same content depending on the property name. See https://forum.open-services.net/t/oslc4j-cannot-get-a-changerequest-that-contains-special-characters/492/11

This PR allows you to use XMLLiteral both as an OSLC ValueType and as a Java property type:

    @OslcValueType(ValueType.XMLLiteral)
    public XMLLiteral getDescription() {
        return description;
    }

This may result in more strict handling of the property value. No existing behaviour is expected to change. See #213 for a helper to check if a String contains valid XML.

Checklist

• This PR adds an entry to the CHANGELOG. See https://keepachangelog.com/en/1.0.0/ for instructions. Minor edits are exempt. Should add an entry after 4.1 release.
• This PR was tested on at least one Lyo OSLC server or adds unit/integration tests.
• This PR does NOT break the API

[berezovskyi]

We did a screenshare review with Jad. The question is if we want to include it in Lyo 4.1 release. I would suggest to keep it for 4.2/5.0.

[jadelkhoury]

I also vote to wait. Then we can use and test it a bit more

[sonarcloud]

SonarCloud Quality Gate failed.   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
2 Code Smells

0.0% Coverage
0.3% Duplication

[sonarcloud]

SonarCloud Quality Gate failed.   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
2 Code Smells

0.0% Coverage
0.3% Duplication

[berezovskyi]

From the run output:

Error:  Errors: 
Error:    XmlLiteralTest.literalTestXmlDatatypeRDF:158->readModel:186 » Riot [line: 5, col: 33] {E211} Base URI is null, but there are relative URIs to resolve.: <>
Error:    XmlLiteralTest.literalTestXmlDatatypeXSD:143->readModel:186 » Riot [line: 5, col: 33] {E211} Base URI is null, but there are relative URIs to resolve.: <>
Error:    XmlLiteralTest.literalTestXmlParsetype:171->readModel:186 » Riot [line: 5, col: 33] {E211} Base URI is null, but there are relative URIs to resolve.: <>
Error:    XmlLiteralTest.roundtripTestXmlDatatypeRDF:54->readModel:186 » Riot [line: 5, col: 33] {E211} Base URI is null, but there are relative URIs to resolve.: <>
Error:    XmlLiteralTest.roundtripTestXmlParsetypeWithAnnotatedLiteralProperty:62->readModel:186 » Riot [line: 6, col: 33] {E211} Base URI is null, but there are relative URIs to resolve.: <>
Error:    XmlLiteralTest.roundtripTestXmlParsetypeWithAnnotatedStringProperty:70->readModel:186 » Riot [line: 6, col: 33] {E211} Base URI is null, but there are relative URIs to resolve.: <>
[INFO] 
Error:  Tests run: 216, Failures: 0, Errors: 6, Skipped: 65

I believe the errors were introduced not due to changes on master in the meantime but due to a more strict RDF parsing in newer Jena versions.