Code improvements / Fix warnings

- Fix CodeQL warnings
- Port lots of improvements/fixes from PR #225
- replace 'array_hexstr' and '%*H' format by sdk function 'format_hex'
- Add 'noreturn' attribute in 'main.c'

src/shared_context.h

@@ -147,7 +147,7 @@ typedef union {
     strDataTmp_t tmp;
 } strings_t;
 
-extern chain_config_t *chainConfig;
+extern const chain_config_t *chainConfig;
 
 extern tmpCtx_t tmpCtx;
 extern txContext_t txContext;