Add mypy check, add missing types and fix type issues

mypy.ini

@@ -0,0 +1,25 @@
+[mypy]
+check_untyped_defs = true
+disallow_any_generics = true
+disallow_incomplete_defs = true
+disallow_untyped_calls = true
+disallow_untyped_decorators = true
+disallow_untyped_defs = true
+disable_error_code = annotation-unchecked
+enable_error_code = ignore-without-code, redundant-self, truthy-iterable
+follow_imports = silent
+local_partial_types = true
+no_implicit_optional = true
+no_implicit_reexport = true
+show_error_codes = true
+strict_concatenate = false
+strict_equality = true
+warn_incomplete_stub = true
+warn_redundant_casts = true
+warn_return_any = true
+warn_unreachable = true
+warn_unused_configs = true
+warn_unused_ignores = true
+
+[mypy-homeassistant.*]
+implicit_reexport = True