feat(composition): added az_to_species binding and added bindings for fourdst exceptions

src-pybind/fourdst/_phys/__init__.pyi

@@ -6,4 +6,5 @@ from . import atomic
 from . import composition
 from . import config
 from . import constants
-__all__: list[str] = ['atomic', 'composition', 'config', 'constants']
+from . import exceptions
+__all__: list[str] = ['atomic', 'composition', 'config', 'constants', 'exceptions']

src-pybind/fourdst/_phys/exceptions.pyi

@@ -0,0 +1,15 @@
+"""
+Exception bindings
+"""
+from __future__ import annotations
+__all__: list[str] = ['CompositionError', 'InvalidCompositionError', 'SpeciesError', 'UnknownSymbolError', 'UnregisteredSymbolError']
+class CompositionError(Exception):
+    pass
+class InvalidCompositionError(CompositionError):
+    pass
+class SpeciesError(Exception):
+    pass
+class UnknownSymbolError(SpeciesError):
+    pass
+class UnregisteredSymbolError(SpeciesError):
+    pass