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/tests/test_cmake_build/test.py

@@ -0,0 +1,8 @@
+import sys
+
+import test_cmake_build
+
+assert isinstance(__file__, str)  # Test this is properly set
+
+assert test_cmake_build.add(1, 2) == 3
+print(f"{sys.argv[1]} imports, runs, and adds: 1 + 2 = 3")