Fix compiler errors with newer FairSoft/FairRoot versions

Add missing include statements.
With FairSoft apr21 and/or FairRoot v18.6.2 some implicitly included
header files aren't found any longer. Add include statements for these
header files explicitly.

analysis/PWGDIL/dielectron/papaframework/PairAnalysisMetaData.cxx

@@ -16,6 +16,7 @@
 ///////////////////////////////////////////////////////////////////////////
 
 #include <TCollection.h>
+#include <TDatime.h>
 #include <TList.h>
 #include <TPad.h>
 #include <TROOT.h>

analysis/PWGDIL/dielectron/papaframework/PairAnalysisSpectrum.cxx

@@ -56,6 +56,7 @@
 #include <TGraphErrors.h>
 #include <TH1.h>
 #include <TList.h>
+#include <TObjString.h>
 #include <TPad.h>
 #include <TPaveText.h>
 #include <TProfile.h>

core/config/CbmConfigBase.h

@@ -12,6 +12,7 @@
 #include <iostream>
 #include <map>
 #include <regex>
+#include <set>
 
 namespace pt = boost::property_tree;
 

fles/cosy2019/unpacker/CbmStsCoincHodo.cxx

@@ -16,6 +16,7 @@
 #include "FairRunOnline.h"
 
 #include "TClonesArray.h"
+#include "TFile.h"
 #include "TH1.h"
 #include "TH2.h"
 #include "TH3.h"

reco/littrack/cbm/qa/material/CbmLitCheckBrem.cxx

@@ -14,6 +14,7 @@
 
 #include <cmath>
 #include <cstdlib>
+#include <iostream>
 
 CbmLitCheckBrem::CbmLitCheckBrem() : fMat("iron") {
   fNofMom = 10;

sim/response/base/CbmDigitization.cxx

@@ -26,6 +26,7 @@
 
 #include "TClonesArray.h"
 #include "TGeoManager.h"
+#include "TObjString.h"
 #include "TROOT.h"
 
 #include <cassert>