SUBMODULE: added OpenQBMM submodule - see #1522

OpenQBMM is a suite of solvers to simulate polydisperse multiphase flows using
Quadrature-Based Moment Methods (QBMM).  For more information, please see
https://www.openqbmm.org/

Main author: Alberto Passalacqua

.gitmodules

@@ -10,3 +10,7 @@
 [submodule "adios"]
 	path = modules/adios
 	url = https://develop.openfoam.com/Community/adiosfoam.git
+[submodule "modules/OpenQBMM"]
+	path = modules/OpenQBMM
+	url = https://github.com/OpenQBMM/OpenQBMM
+	branch = openfoam.com

OpenQBMM @ 7f6277c8

+Subproject commit 7f6277c83f403f91644cb1aac471e0e16319aba5