Merge branch 'release-0.9' into 'main'

CHANGELOG.md

DEPENDENCIES.md

FEATURES.md

README.md

README_SETUP.md

RELEASE_GUIDELINES.md

caosdb-proto

caosdb-webui

pom.xml

src/doc/CaosDB-Query-Language.md

src/doc/conf.py

src/doc/entities.png

src/doc/entities.svg

src/doc/roles.md

src/doc/specification/AbstractProperty.md

src/doc/specification/Datatype.md

src/doc/specification/RecordType.rst

...main/java/org/caosdb/server/datatype/BooleanDatatype.java

src/main/java/org/caosdb/server/datatype/DoubleDatatype.java

...main/java/org/caosdb/server/datatype/IntegerDatatype.java