Rewrite TMVA generated code in Rec/ChargedProtoANNPID/src/tmva

• Add a script rewrite-TMVA-generated-code.py which rewrites TMVA generated MVAs to make them faster to compile, easier to link, and thread-safe...
• apply the above script on the code in Rec/ChargedProtoANNPID/src/tmva

Backport of !1877 (merged) from master

added PID cleanup thread-safety labels

added all-slots label

• [2020-01-23 00:06] Validation started with lhcb-run2-patches-dev4#214
• [2020-01-23 00:07] Validation started with lhcb-run2-patches#645
• [2020-01-24 00:08] Validation started with lhcb-run2-patches-dev4#215
• [2020-01-24 00:12] Validation started with lhcb-run2-patches#646
• [2020-01-25 00:06] Validation started with lhcb-run2-patches-dev4#216
• [2020-01-25 00:07] Validation started with lhcb-run2-patches#647
• [2020-01-26 00:05] Validation started with lhcb-run2-patches-dev4#217
• [2020-01-27 00:10] Validation started with lhcb-run2-patches#648
• [2020-01-27 00:11] Validation started with lhcb-run2-patches-dev4#218
• [2020-01-28 00:08] Validation started with lhcb-run2-patches-dev4#219
• [2020-01-28 00:13] Validation started with lhcb-run2-patches#649

changed title from backport master tmva rewrite to Rewrite TMVA generated code in Rec/ChargedProtoANNPID/src/tmva

changed the description

mentioned in commit 23e46cb4

merged

removed all-slots label