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

Python/errors.c

@@ -1241,8 +1241,12 @@ static PyStructSequence_Desc UnraisableHookArgs_desc = {
 
 
 PyStatus
-_PyErr_InitTypes(void)
+_PyErr_InitTypes(PyInterpreterState *interp)
 {
+    if (!_Py_IsMainInterpreter(interp)) {
+        return _PyStatus_OK();
+    }
+
     if (UnraisableHookArgsType.tp_name == NULL) {
         if (PyStructSequence_InitType2(&UnraisableHookArgsType,
                                        &UnraisableHookArgs_desc) < 0) {