Import Katoptron from Waves

This first MR imports the code from the old waves repository.

CMake/FindMPI4PY.cmake

+# Copyright 2022 University of Liège
+# 
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+# 
+#     http://www.apache.org/licenses/LICENSE-2.0
+# 
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+if(NOT MPI4PY_INCLUDE_DIR)
+    execute_process(COMMAND
+      "${PYTHON_EXECUTABLE}" "-c" "import mpi4py; print(mpi4py.get_include())"
+      OUTPUT_VARIABLE MPI4PY_INCLUDE_DIR
+      RESULT_VARIABLE MPI4PY_COMMAND_RESULT
+      OUTPUT_STRIP_TRAILING_WHITESPACE)
+    if(MPI4PY_COMMAND_RESULT)
+        message("waves/CMake/FindMPI4PY: mpi4py not found")
+        set(MPI4PY_FOUND FALSE)
+    else(MPI4PY_COMMAND_RESULT)
+        if (MPI4PY_INCLUDE_DIR MATCHES "Traceback")
+            message("waves/CMake/FindMPI4PY: mpi4py matches traceback")
+            ## Did not successfully include MPI4PY
+            set(MPI4PY_FOUND FALSE)
+        else (MPI4PY_INCLUDE_DIR MATCHES "Traceback")
+            ## successful
+            set(MPI4PY_FOUND TRUE)
+            set(MPI4PY_INCLUDE_DIR ${MPI4PY_INCLUDE_DIR} CACHE STRING "mpi4py include path")
+        endif (MPI4PY_INCLUDE_DIR MATCHES "Traceback")
+    endif(MPI4PY_COMMAND_RESULT)
+else(NOT MPI4PY_INCLUDE_DIR)
+    set(MPI4PY_FOUND TRUE)
+endif(NOT MPI4PY_INCLUDE_DIR)
+# ----------------------------------------------------------------------------
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(MPI4PY DEFAULT_MSG
+				MPI4PY_INCLUDE_DIR)