[#922] Easier use of journal extract data for troubleshooting and forensics

Complete implementation of %YDBJNLF functionality. The complete functionality is described in the Draft Release Notes of #922. INGEST executes MUPIP JOURNAL EXTRACT FORWARD SHOW=ALL FENCES=NONE NOVERIFY DETAIL FULL of a journal file in a PIPE device, to extract data and metadata into global variables as documented. Entryrefs also exist to output an Octo DDL of the data as well as to purge ingested data. Also:

• INGEST issues error if asked to ingest a file that is not a journal file. It does this by ensuring that the first three lines of stderr of the MUPIP JOURNAL EXTRACT process start with %XXX-I-MUJNLSTAT, where XXX is $ydb_msgprefix (defaulting to "YDB").
• INGEST^%YDBJNLF() returns 1 if it created a new YDBJNLF region, and reloaded $ZGBLDIR; 0 otherwise.
• The call to OCTODDL with no parameters outputs the complete Octo DDL, not just DDL for the metadata.
• Move creation of YDBJNLF region from sourcing %YDBENV to calling INGEST^%YDBJNLF.
• Environment variables in the filename specification in the DEFAULT segment are preserved when creating filenames for additional regions.
• Fix bugs found in bench testing and indirectly when reviewing the draft release note.
• Some minor formatting cleanup.