HPCC-8556 Refactor const char * query functions from helpers

Return roxiemem-allocated strings rather than having to store in context in
order to release.

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
HPCC-8556 Refactor const char * query functions from helpers

Rename some queryXXX functions to getXXX and support values that are not
compile-time constant.

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
HPCC-8556 Refactor const char * query functions from helpers

Final batch

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
HPCC-8556 Refactor const char * query functions from helpers

Optimize  getString() calls from codegen separately for varstring versus
string, to keep generated code size to a minimum.

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
HPCC-8556 Refactor const char * query functions from helpers

Removed some unusued methods from context.

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
HPCC-8556 Refactor const char * query functions from helpers

Renamed context method to something a little clearer.
Other minor changes from code review.

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
HPCC-8556 Refactor const char * query functions from helpers

Change queryAlgorithm and queryCluster to complete the set.

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
HPCC-8556 Refactor const char * query functions from helpers

More cleanup of dead code and out-of-date comments.

Signed-off-by: Richard Chapman <rchapman@hpccsystems.com>
Merge pull request #4019 from richardkchapman/char-star-returns

HPCC-8556 Refactor const char * query functions from helpers

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>