Add static GetBranchName function to digis

Since, we do not use the class name in our output branches I added a GetBranchName() function for all digis connected to the mcbm2021 beamtime. @todo add the function to other digis (much,mvd).

core/data/psd/CbmPsdDigi.h

@@ -91,6 +91,12 @@ public:
   UInt_t GetAddress() const { return fuAddress; };
 
 
+  /** @brief Get the desired name of the branch for this obj in the cbm output tree  (static)
+   ** @return "PsdDigi"
+   **/
+  static const char* GetBranchName() { return "PsdDigi"; }
+
+
   /** @brief Time
        ** @return Time [ns]
        **/

core/data/rich/CbmRichDigi.h

@@ -40,6 +40,11 @@ public:
 	 */
   Int_t GetAddress() const { return fAddress; }
 
+  /** @brief Get the desired name of the branch for this obj in the cbm output tree  (static)
+   ** @return "RichDigi"
+   **/
+  static const char* GetBranchName() { return "RichDigi"; }
+
   /** @brief Charge
 	 ** @return Returns TOT as charge
 	 **

core/data/sts/CbmStsDigi.h

@@ -62,6 +62,12 @@ public:
   Int_t GetAddress() const { return fAddress; }
 
 
+  /** @brief Get the desired name of the branch for this obj in the cbm output tree  (static)
+   ** @return "StsDigi"
+   **/
+  static const char* GetBranchName() { return "StsDigi"; }
+
+
   /** @brief Channel number in module
    ** @value Channel number
    **/

core/data/tof/CbmTofDigi.h

@@ -96,6 +96,12 @@ public:
   Int_t GetAddress() const { return fuAddress; };
 
 
+  /** @brief Get the desired name of the branch for this obj in the cbm output tree  (static)
+   ** @return "TofDigi"
+   **/
+  static const char* GetBranchName() { return "TofDigi"; }
+
+
   /** @brief Class name (static)
        ** @return  string CbmTofDigi
        **/