bpo-36763: Implement the PEP 587 (GH-13592)

* Add a whole new documentation page:
  "Python Initialization Configuration"
* PyWideStringList_Append() return type is now PyStatus,
  instead of int
* PyInterpreterState_New() now calls PyConfig_Clear() if
  PyConfig_InitPythonConfig() fails.
* Rename files:

  * Python/coreconfig.c => Python/initconfig.c
  * Include/cpython/coreconfig.h => Include/cpython/initconfig.h
  * Include/internal/: pycore_coreconfig.h => pycore_initconfig.h

* Rename structures

  * _PyCoreConfig => PyConfig
  * _PyPreConfig => PyPreConfig
  * _PyInitError => PyStatus
  * _PyWstrList => PyWideStringList

* Rename PyConfig fields:

  * use_module_search_paths => module_search_paths_set
  * module_search_path_env => pythonpath_env

* Rename PyStatus field: _func => func
* PyInterpreterState: rename core_config field to config
* Rename macros and functions:

  * _PyCoreConfig_SetArgv() => PyConfig_SetBytesArgv()
  * _PyCoreConfig_SetWideArgv() => PyConfig_SetArgv()
  * _PyCoreConfig_DecodeLocale() => PyConfig_SetBytesString()
  * _PyInitError_Failed() => PyStatus_Exception()
  * _Py_INIT_ERROR_TYPE_xxx enums => _PyStatus_TYPE_xxx
  * _Py_UnixMain() => Py_BytesMain()
  * _Py_ExitInitError() => Py_ExitStatusException()
  * _Py_PreInitializeFromArgs() => Py_PreInitializeFromBytesArgs()
  * _Py_PreInitializeFromWideArgs() => Py_PreInitializeFromArgs()
  * _Py_PreInitialize() => Py_PreInitialize()
  * _Py_RunMain() => Py_RunMain()
  * _Py_InitializeFromConfig() => Py_InitializeFromConfig()
  * _Py_INIT_XXX() => _PyStatus_XXX()
  * _Py_INIT_FAILED() => _PyStatus_EXCEPTION()

* Rename 'err' PyStatus variables to 'status'
* Convert RUN_CODE() macro to config_run_code() static inline function
* Remove functions:

  * _Py_InitializeFromArgs()
  * _Py_InitializeFromWideArgs()
  * _PyInterpreterState_GetCoreConfig()
diff --git a/Python/bootstrap_hash.c b/Python/bootstrap_hash.c
index fe71cc3..43f5264 100644
--- a/Python/bootstrap_hash.c
+++ b/Python/bootstrap_hash.c
@@ -1,5 +1,5 @@
 #include "Python.h"
-#include "pycore_coreconfig.h"
+#include "pycore_initconfig.h"
 #ifdef MS_WINDOWS
 #  include <windows.h>
 /* All sample MSDN wincrypt programs include the header below. It is at least
@@ -547,14 +547,14 @@
 }
 
 
-_PyInitError
-_Py_HashRandomization_Init(const _PyCoreConfig *config)
+PyStatus
+_Py_HashRandomization_Init(const PyConfig *config)
 {
     void *secret = &_Py_HashSecret;
     Py_ssize_t secret_size = sizeof(_Py_HashSecret_t);
 
     if (_Py_HashSecret_Initialized) {
-        return _Py_INIT_OK();
+        return _PyStatus_OK();
     }
     _Py_HashSecret_Initialized = 1;
 
@@ -579,11 +579,11 @@
            pyurandom() is non-blocking mode (blocking=0): see the PEP 524. */
         res = pyurandom(secret, secret_size, 0, 0);
         if (res < 0) {
-            return _Py_INIT_ERR("failed to get random numbers "
+            return _PyStatus_ERR("failed to get random numbers "
                                 "to initialize Python");
         }
     }
-    return _Py_INIT_OK();
+    return _PyStatus_OK();
 }