bpo-46008: Make runtime-global object/type lifecycle functions and state consistent. (gh-29998)

This change is strictly renames and moving code around.  It helps in the following ways:

* ensures type-related init functions focus strictly on one of the three aspects (state, objects, types)
* passes in PyInterpreterState * to all those functions, simplifying work on moving types/objects/state to the interpreter
* consistent naming conventions help make what's going on more clear
* keeping API related to a type in the corresponding header file makes it more obvious where to look for it

https://bugs.python.org/issue46008

Include/internal/pycore_pyerrors.h

@@ -8,6 +8,14 @@ extern "C" {
 #  error "this header requires Py_BUILD_CORE define"
 #endif
 
+
+/* runtime lifecycle */
+
+extern PyStatus _PyErr_InitTypes(PyInterpreterState *);
+
+
+/* other API */
+
 static inline PyObject* _PyErr_Occurred(PyThreadState *tstate)
 {
     assert(tstate != NULL);