HPCC-10749 Search WU/Query with non-existence of property/attr

Using the existing code, WUQuery?State=unknown does not return "unknown"
WUs. The "unknown" WUs are WUs which do not have the @state or @state =
"". We do not suport any xpath syntax that allow you to test for the non
-existence of a property or attribute. In this fix, the code is added to
filter ECL WUs (and DFU WU, Query) with non-existence of a property or
attribute.
HPCC-10749 Revise based on code review

1. Clone 'unknownAttributes'; 2. Use sortElements to avoid duplicated
code; 3. Move 'cSort sort' into block; 4. Use simple array lookup.
HPCC-10749 Rebase and remove extra checks, etc.
HPCC-10696 Roxie should limit size of workunit outputs

Both a default limit (10Mb) and an overridable one via MAXSIZE attribute.

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
HPCC-10696 Roxie should limit size of workunit outputs

Fix cosmetic issue in error message, spotted when testing.

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
HPCC-9556 Refactor warning handling and implement #ONWARNING

This patch restructures the warning handling so it is always reported via the
report() virtual, and also maps the warning levels using the same chain.

eclcc now supports -w<n>=option to configure the behaviour for a particular warning.

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>

HPCC-9556 Change error into a severity

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>

HPCC-9556 Fix regression from first commit

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>