Add MCPLFLAGS in these config snips

Author: willend

tools/Python/mctest/mcstas-test/McStas_8GPU/mccode_config.json

@@ -24,6 +24,7 @@
     "OACCFLAGS": "-fast -Minfo=accel -acc=gpu -gpu=mem:managed -DOPENACC",
     "GSLFLAGS": "-Wl,-rpath,GETPATH(miniconda3/lib) -LGETPATH(miniconda3/lib) -lgsl -lgslcblas -IGETPATH(miniconda3/include)",
     "NCRYSTALFLAGS": "CMD(ncrystal-config --show buildflags)",
+    "MCPLFLAGS": "-Wl,-rpath,CMD(mcpl-config --show libdir) -Wl,CMD(mcpl-config --show libpath) -ICMD(mcpl-config --show includedir)",
     "XRLFLAGS": "",
     "CC": "gcc",
     "OACC": "nvc",

tools/Python/mctest/mcxtrace-test/McXtrace_8GPU/mccode_config.json

@@ -24,6 +24,7 @@
     "OACCFLAGS": "-fast -Minfo=accel -acc=gpu -gpu=mem:managed -DOPENACC",
     "GSLFLAGS": "-Wl,-rpath,GETPATH(miniconda3/lib) -LGETPATH(miniconda3/lib) -lgsl -lgslcblas -IGETPATH(miniconda3/include)",
     "NCRYSTALFLAGS": "",
+    "MCPLFLAGS": "-Wl,-rpath,CMD(mcpl-config --show libdir) -Wl,CMD(mcpl-config --show libpath) -ICMD(mcpl-config --show includedir)",
     "XRLFLAGS": "-Wl,-rpath,GETPATH(miniconda3/lib) -LGETPATH(miniconda3/lib) -lxrl -IGETPATH(miniconda3/include)",
     "CC": "gcc",
     "OACC": "nvc",