Remove Workflow/ADAG XML (DAX) format and dead org.griphyn.vdl legacy code #2236

Description
Remove the legacy Workflow/ADAG XML (DAX) format now that YAML is the only supported workflow format, and remove the now-dead org.griphyn.vdl.* Chimera/VDS legacy tree it was the last live tie to. Concretely:

• DAX XML parsing (parser/dax/DAXParser2.java, DAXParser3.java), DAXParserFactory simplified to YAML-only (DAXParser5)
• ADAG.java's XML-writing implementation (toXML, deprecated writeToWriter, mWriter/XMLWriter) — the FORMAT enum and writeToFile/writeTo/writeToSTDOUT overloads are kept so a future format can still be added
• Unshipped ranking/{Rank,Ranking}.java and client/DAXValidator.java SAX/XSD validator tool
• 8 DAX XSD schema files (share/pegasus/schema/dax-{2.0,2.1,3.0,3.2,3.3,3.4,3.5,3.6}.xsd)
• 193 of 203 files under org.griphyn.vdl.* (the old Chimera/Virtual Data System ancestor tree — VDL compiler, VDC database schema/driver layer, old DAX-XML router/planner, annotation system) confirmed unreachable from any shipped bin/ tool or the live planning pipeline; keeps only toolkit/Toolkit.java, util/{ChimeraProperties,Logging}.java, and the euryale file-factory classes that back the live Flat/Hashed output/staging/submit mappers
• Adjacent dead code whose only purpose was holding a few of those org.griphyn.vdl classes alive: planner.partitioner.{SingleLook,MultipleLook,DAXWriter,PDAXWriter,WriterCallback} (old DAX-partitioning feature, never wired into PartitionerFactory), planner.client.ExitCode.java (no bin/ wrapper, superseded by the Python pegasus-exitcode), and planner.invocation.* + parser.{InvocationParser,IVSElement,IVPTest}.java (kickstart-invocation-XML parsing, zero live callers)

Motivation
DAX/ADAG XML has been superseded by the YAML workflow format. Once XML parsing is gone, the org.griphyn.vdl.* tree it was the only remaining tie to becomes dead weight, along with a few small dead subsystems that were only keeping isolated pieces of it referenced.

Acceptance Criteria

• DAXParserFactory only loads the YAML (DAXParser5) parser
• ADAG.java retains the FORMAT enum/extensibility scaffold but only implements YAML output
• Confirmed-dead org.griphyn.vdl.* files, ExitCode.java, planner.invocation.*, InvocationParser/IVSElement/IVPTest, and the dead DAX-partitioning classes are removed along with their tests
• Full Java test suite passes with zero regressions

Additional context
Companion to the SC-XML/TC-Text catalog format removal (issue #2235) — together these complete the move to YAML as the sole catalog/workflow format.