Fix TiGL not opening CPACS v3.5 data sets

[MarAlder]

This change enables TiGL to search for the cpacsVersion element according to both CPACS v<3.5 and v>=3.5.

Description

See #1009 for discussions on this topic.

A new CPACS v3.5 header could look like this:

  <header>
    <name>Cpacs2Test</name>
    <description>Test file to check versioning according to new CPACS header</description>
    <version>2.0.0</version>
    <versionInfos>
      <versionInfo version="2.0.0">
        <description>Test for version 2.0.0</description>
        <cpacsVersion>3.5</cpacsVersion>
        <creator>Marko Alder</creator>
        <timestamp>2024-05-31T10:00:00</timestamp>
      </versionInfo>
      <versionInfo version="1.0.0">
        <description>Test for version 1.0.0</description>
        <cpacsVersion>3.3</cpacsVersion>
        <creator>Marko Alder</creator>
        <timestamp>2024-05-30T10:00:00</timestamp>
      </versionInfo>
    </versionInfos>
  </header>

I suggest that the default behavior is already to search for the versionElement in the versionInfo node, as this is always the most up-to-date in case of doubt (currently CPACS XSD still allows the element in the old location, where it is labeled as deprecated). As soon as TiGL has been upgraded to v3.5, we could also return a deprecation warning.

Since the query is only made via XPath, changes to the generated classes have no influence on the version query (as far as I have seen). Nevertheless, I have generated the classes up to the versionInfo element, as they were previously also available for the old update node.

This would fix #1009.

How Has This Been Tested?

• I added a new unittest CPACSVersion.newCPACSHeader
• I opened old and new CPACS files in TiGL viewer and checked the output

Screenshots, that help to understand the changes(if applicable):

Current behavior:

New behavior:

Checklist:

• A test for the new functionality was added.
• All tests run without failure.
• The new code complies with the TiGL style guide.
• New classes have been added to the Python interface.
• API changes were documented properly in tigl.h.

[joergbrech]

Nice! Thanks a lot @MarAlder.

PS: If needed, we could add the versionInfo change also to this tool: https://github.com/DLR-SC/cpacs2to3