Add Python client for GetGlobalMetrics service with time range and statistics filtering#136

Copilot wants to merge 2 commits intocandidate-9.12.xjakesmith/HPCC-Platform:candidate-9.12.xfrom

copilot/fix-3c1f9170-f749-49a5-a8e1-2ca29ef0ef7cjakesmith/HPCC-Platform:copilot/fix-3c1f9170-f749-49a5-a8e1-2ca29ef0ef7cCopy head branch name to clipboard