Python: split module initialization from WSGI implementation.

This is required for futher ASGI implementation.

src/python/nxt_python.h

@@ -0,0 +1,31 @@
+
+/*
+ * Copyright (C) NGINX, Inc.
+ */
+
+#ifndef _NXT_PYTHON_H_INCLUDED_
+#define _NXT_PYTHON_H_INCLUDED_
+
+
+#include <Python.h>
+#include <nxt_unit.h>
+
+
+extern PyObject  *nxt_py_application;
+
+typedef struct {
+    nxt_str_t  string;
+    PyObject   **object_p;
+} nxt_python_string_t;
+
+nxt_int_t nxt_python_init_strings(nxt_python_string_t *pstr);
+void nxt_python_done_strings(nxt_python_string_t *pstr);
+
+void nxt_python_print_exception(void);
+
+nxt_int_t nxt_python_wsgi_init(nxt_task_t *task, nxt_unit_init_t *init);
+int nxt_python_wsgi_run(nxt_unit_ctx_t *ctx);
+void nxt_python_wsgi_done(void);
+
+
+#endif  /* _NXT_PYTHON_H_INCLUDED_ */