ulp: refactor ulp component

This commit refactors the ulp component.
Files are now divided based on type of ulp, viz., fsm or risc-v.
Files common to both are maintained in the ulp_common folder.

This commit also adds menuconfig options for ULP within the ulp
component instead of presenting target specific configuations for ulp.

components/ulp/ulp_common/include/esp32/ulp_common_defs.h

@@ -0,0 +1,19 @@
+/*
+ * SPDX-FileCopyrightText: 2022 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#ifndef __ULP_COMMON_DEFS_H__
+#define __ULP_COMMON_DEFS_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define RTC_SLOW_MEM ((uint32_t*) 0x50000000)       /*!< RTC slow memory, 8k size */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // __ULP_COMMON_DEFS_H__