Re-instate VMM shaper

This reverts merge request !37433 (merged)

Re-adding VMM shaper and sync with 21.3/master ahead of optimizations being applied to top to address excessive CPU usage.

@pscholer @rosati @nkoehler

added 21.9 Digitization MuonSpectrometer labels

This merge request affects 5 files:

• MuonSpectrometer/MuonDigitization/MM_Digitization/MM_Digitization/MM_ElectronicsResponseSimulation.h
• MuonSpectrometer/MuonDigitization/MM_Digitization/MM_Digitization/VMM_Shaper.h
• MuonSpectrometer/MuonDigitization/MM_Digitization/src/MM_DigitizationTool.cxx
• MuonSpectrometer/MuonDigitization/MM_Digitization/src/MM_ElectronicsResponseSimulation.cxx
• MuonSpectrometer/MuonDigitization/MM_Digitization/src/VMM_Shaper.cxx

Adding @jchapman ,@rosati ,@wleight ,@vpascuzz ,@nkoehler as watchers

added review-pending-level-1 label

CI Result SUCCESS (hash bb17b243)

	Athena
externals
cmake
make
required tests
optional tests

Full details available on this CI monitor view
Athena: number of compilation errors 0, warnings 24
For experts only: Jenkins output [CI-MERGE-REQUEST-CC7 45110]

Changes look fine, tests pass with fewer warnings than nightlies, none obviously related to this MR. L1 approving.

added review-approved label and removed review-pending-level-1 label

merged

mentioned in commit 00daf0ce

added sweep:ignore label