HPCC-12046 Reimplement the graph and other statistics

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
HPCC-12046 Changes following review

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
HPCC-12046 Change stats to use hash table and a value array

Also switch to using a StatsScopeId class, and clean up other code

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #6372 from ghalliday/issue12046

HPCC-12046 Refactor statistics

Reviewed-By: Jake Smith <jake.smith@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>