…d JDK 21 (#692)

Additionally: 

* Refactor build tool tests to support running under any JDK

We introduce the concept of Tool, which has restrictions on
minimum/maximum JDK version it can run under.
We also use external JDK version to conditionally ignore tests.

…play_name (#677 #707)

* Update Document from upstream scip.proto

This copies the latest additions to the Document message:
 * a new language field and Language enum
 * a new text field, to embed the document content itself.
This is meant for the new SymbolInformation::signature_documentation
field.

This also updates some documentation comments.

* Update SymbolInformation from upstream scip.proto

This copies the latest additions to the SymbolInformation message:
 * the documentation field is explicitly not meant for signature
   documentation anymore, instead a new signature_documentation field
   is added
 * a new display_name field is added
 * a new enclosing_symbol field is added for local symbols
 * a new kind field is added along with a Kind enum to have a
   finer-grained classification than the one provided by descriptor
   suffixes (and is especially useful for local symbols which don't
   have suffixes)

* Forward display_name from SemanticDB to SCIP

The SemanticDB schema already provides a display_name field, forward it
to the SCIP output in scip-semanticdb.
This also adds support to the ScipPrinters testing utility and updates
the tests accordingly.

* Move signature documentation to its new dedicated field

SemanticDB provides a structured version of the signature in the
signature field. Instead of turning it into a markdown-encoded string
for the documentation field, this builds a Document for the
signature_documentation field.

This also updates the ScipPrinters testing utility and the tests
accordingly.

* Add back SemanticDB SymbolInformation::owner field

SemanticDB used to have a SymbolInformation::owner field with id 15.
This re-introduces the field with the same semantics under the name
enclosing_symbol.

To be able to re-use the field 15, this moves the out-of-spec
definition_relationships field to id 21.

* Forward enclosing_symbol from SemanticDB to SCIP

This also adds support to the ScipPrinters testing utility.

* Populate SymbolInformation::enclosing_symbol in semanticdb-javac

This only populates the enclosing_symbol for local symbols, and updates
the tests accordingly.

* Build SCIP kind from SematicDB kind and properties

This also updates the ScipPrinters testing utility and the tests
accordingly.

* semanticdb-javac: set kind to Variable for local variables

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Co-authored-by: Nicolas Guichard <nicolas.guichard@kdab.com>