Thesaurus / Add support for thesaurus described using OWL format

[fxprunayre]

A number of DCAT related vocabularies are published using OWL format describing a concept schema and concepts. eg. https://mobilitydcat-ap.github.io/controlled-vocabularies/network-coverage/latest/index.html
Concepts are described using:

<owl:NamedIndividual rdf:about="https://w3id.org/mobilitydcat-ap/mobility-theme/accesibility-information-for-vehicles">
    <rdf:type rdf:resource="http://www.w3.org/2004/02/skos/core#Concept"/>
    <skos:broader rdf:resource="https://w3id.org/mobilitydcat-ap/mobility-theme/data-content-sub-category"/>
    <skos:broader rdf:resource="https://w3id.org/mobilitydcat-ap/mobility-theme/public-transport-non-scheduled-transport"/>
    <skos:inScheme rdf:resource="https://w3id.org/mobilitydcat-ap/mobility-theme"/>
    <skos:prefLabel xml:lang="en">Accesibility information for vehicles</skos:prefLabel>
</owl:NamedIndividual>

Add the possibility to import those files directly by converting them from OWL to SKOS format supported by GeoNetwork. Also support broader/narrower terms.

API changes:

• when using the stylesheet parameter of the upload thesaurus operation, restrict the use to known file in xslt/services/thesaurus/ folder.

Also some Sonar lint items.

Funded by Wallonia region (SPW)

Checklist

• I have read the contribution guidelines
• Pull request provided for main branch, backports managed with label
• Good housekeeping of code, cleaning up comments, tests, and documentation
• Clean commit history broken into understandable chucks, avoiding big commits with hundreds of files, cautious of reformatting and whitespace changes
• Clean commit messages, longer verbose messages are encouraged
• API Changes are identified in commit messages
• Testing provided for features or enhancements using automatic tests
• User documentation provided for new features or enhancements in manual
• Build documentation provided for development instructions in README.md files
• Library management using pom.xml dependency management. Update build documentation with intended library use and library tutorials or documentation

[sonarcloud]

Quality Gate failed

Failed conditions

0.0% Coverage on New Code (required ≥ 80%)

See analysis details on SonarCloud

[josegar74]

Tested, works fine. Code changes look good.

[ianwallen]

@fxprunayre

I noticed that you added MediaType.APPLICATION_XML_VALUE
However this function uses the following content type.

response.setContentType("text/xml");

If someone calls the api requesting MediaType.APPLICATION_XML_VALUE, I think they would expect MediaType.APPLICATION_XML_VALUE and not MediaType.TEXT_XML_VALUE

Should

response.setContentType("text/xml");

Be replaced with

String acceptHeader = StringUtils.isBlank(request.getHeader(HttpHeaders.ACCEPT)) ? MediaType.TEXT_XML_VALUE : request.getHeader(HttpHeaders.ACCEPT);
response.setContentType(acceptHeader);