Packaging, installation, and licensing changes

SaxonJ 12.0 to 12.5 are built and tested using Java 11, and from 12.6 is built and tested using Java 21, but is supported with Java 8 or later.

Note: Saxon 12.0 did not work under Java 8; this is fixed in Saxon 12.1.

Note: Saxon 12.6 did not work under Java 8; this is fixed in Saxon 12.7.