Add cut for pion band rejection, extend the TPC electron selection to…

[feisenhu]

… match MC

I included a new cut to reject the pions as a band within the TPC dE/dx spectra.

Additionally I increased the electron selection of the TPC up to 100 in order to be able to compare the result with MC.

[alibuild]

Error while checking build/O2Physics/o2 for 1de624b at 2022-07-21 14:54:

## sw/BUILD/O2-latest/log
/sw/SOURCES/O2/nightly-20220721/nightly-20220721/Framework/Core/src/ArrowSupport.cxx:537:1: fatal error: error writing to /tmp/ccRo5ZWO.s: No space left on device
/sw/SOURCES/O2/nightly-20220721/nightly-20220721/Framework/Core/src/CommonMessageBackends.cxx:131:27: fatal error: error writing to /tmp/cccqLxil.s: No space left on device
/sw/SOURCES/O2/nightly-20220721/nightly-20220721/Framework/Core/src/ControlService.cxx:88:1: fatal error: error writing to /tmp/ccKJEc3M.s: No space left on device
/sw/SOURCES/O2/nightly-20220721/nightly-20220721/Framework/Core/src/AnalysisHelpers.cxx:46:1: fatal error: error writing to /tmp/ccO7D2z7.s: No space left on device
/sw/SOURCES/O2/nightly-20220721/nightly-20220721/Framework/Core/src/DataInputDirector.cxx:633:1: fatal error: error writing to /tmp/ccwgrjSP.s: No space left on device
/sw/SOURCES/O2/nightly-20220721/nightly-20220721/Framework/Core/src/CommonServices.cxx:956:27: fatal error: error writing to /tmp/ccJxI2Mz.s: No space left on device
/sw/SOURCES/O2/nightly-20220721/nightly-20220721/Framework/Utils/test/test_RootTreeWriter.cxx:332:1: fatal error: error writing to /tmp/ccf9PgPO.s: No space left on device
/sw/SOURCES/O2/nightly-20220721/nightly-20220721/Framework/Core/src/CompletionPolicyHelpers.cxx:235:27: fatal error: error writing to /tmp/cc9K6iUf.s: No space left on device
/sw/SOURCES/O2/nightly-20220721/nightly-20220721/Framework/Core/test/test_ASoA.cxx:983:1: fatal error: error writing to /tmp/ccEWtd0O.s: No space left on device
/sw/SOURCES/O2/nightly-20220721/nightly-20220721/Framework/Core/src/AODReaderHelpers.cxx:186:1: fatal error: error writing to /tmp/ccBKT5XO.s: No space left on device
ninja: build stopped: subcommand failed.

Full log here.