Implement source debugging for interpreter and AOT (#769)

Implement source debugging feature for classic interpreter and AOT:
- use `cmake -DWAMR_BUILD_DEBUG_INTERP=1` to enable interpreter debugging
- use `cmake -DWAMR_BUILD_DEBUG_AOT=1` to enable AOT debugging

See doc/source_debugging.md for more details.

core/iwasm/libraries/debug-engine/handler.h

@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 2021 Ant Group.  All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ */
+
+#ifndef HANDLER_H
+#define HANDLER_H
+
+#include "gdbserver.h"
+
+void
+handle_generay_set(WASMGDBServer *server, char *payload);
+
+void
+handle_generay_query(WASMGDBServer *server, char *payload);
+
+void
+handle_v_packet(WASMGDBServer *server, char *payload);
+
+void
+handle_threadstop_request(WASMGDBServer *server, char *payload);
+
+void
+handle_set_current_thread(WASMGDBServer *server, char *payload);
+
+void
+handle_get_register(WASMGDBServer *server, char *payload);
+
+void
+handle_get_json_request(WASMGDBServer *server, char *payload);
+
+void
+handle_get_read_binary_memory(WASMGDBServer *server, char *payload);
+
+void
+handle_get_read_memory(WASMGDBServer *server, char *payload);
+
+void
+handle_get_write_memory(WASMGDBServer *server, char *payload);
+
+void
+handle_add_break(WASMGDBServer *server, char *payload);
+
+void
+handle_remove_break(WASMGDBServer *server, char *payload);
+
+void
+handle_continue_request(WASMGDBServer *server, char *payload);
+
+void
+handle_kill_request(WASMGDBServer *server, char *payload);
+
+void
+handle____request(WASMGDBServer *server, char *payload);
+#endif