Merge remote-tracking branch 'github/upgrade_to_java_17'
HTML manual is removed since Elyxer is gone. Install4j is updated to V11. Lyx is updated.
miscellaneous tests are modded in a minor way
Deprecated Java is upgraded to 17
Divers small changes
Remove DNS lookup for client name in httpd
Add description of headers in httpd
Update azure-pipelines.yml for Azure Pipelines