Add gitignore rules for all folders created for externals

.gitignore

+geometry
+input
+parameters

external/.gitignore

+DataTree
+DataTreeQA
+KFParticle
+NicaFemto
+Vc
+cppzmq
+flib_dpb/flib_dpb
+flib_dpb_20
+ipc/ipc
+ipc_legacy/ipc
+jsroot
+spadic/spadic
+