Hardcopy of pybind11 instead of using git submodules (#552)

* removed pybind as submodule
* added hardcopy of pybind11 2.10.0
* rename pybind11 folder to avoid conflicts when changing branch

Co-authored-by: Dhanya Thattil <dhanya.thattil@psi.ch>

libs/pybind/pybind11/__main__.py

@@ -0,0 +1,49 @@
+# pylint: disable=missing-function-docstring
+
+import argparse
+import sys
+import sysconfig
+
+from .commands import get_cmake_dir, get_include
+
+
+def print_includes() -> None:
+    dirs = [
+        sysconfig.get_path("include"),
+        sysconfig.get_path("platinclude"),
+        get_include(),
+    ]
+
+    # Make unique but preserve order
+    unique_dirs = []
+    for d in dirs:
+        if d and d not in unique_dirs:
+            unique_dirs.append(d)
+
+    print(" ".join("-I" + d for d in unique_dirs))
+
+
+def main() -> None:
+
+    parser = argparse.ArgumentParser()
+    parser.add_argument(
+        "--includes",
+        action="store_true",
+        help="Include flags for both pybind11 and Python headers.",
+    )
+    parser.add_argument(
+        "--cmakedir",
+        action="store_true",
+        help="Print the CMake module directory, ideal for setting -Dpybind11_ROOT in CMake.",
+    )
+    args = parser.parse_args()
+    if not sys.argv[1:]:
+        parser.print_help()
+    if args.includes:
+        print_includes()
+    if args.cmakedir:
+        print(get_cmake_dir())
+
+
+if __name__ == "__main__":
+    main()