[FL-3884] Proper integer parsing (#3839)

* feat: strint_to_uint32 and tests
* fix: permit explicit bases and prefixes
* feat: strint_to_{int32,uint16,int16}
* feat: strint_to_u?int64
* refactor: replace strtol, strtoul, sscanf with strint_to_*
* fix: api symbols
* docs: document parameter `end` of strint_to_uint_32
* style: apply changes requested by hedger
* refactor: fix pvs-studio diagnostic
* style: apply changes requested by CookiePLMonster
* fix: unused var
* fix: pointer type
* refactor: convert atoi to strint_to_*
* fix: strint_to_uint8 doesn't actually exist ._ .
* fix: memory leak
* style: address review comments
* Toolbox: couple small comments in the code and doxygen comment update. SubGhz, Loader: fix strint usage.
* Loader: fix incorrect cast

Co-authored-by: あく <alleteam@gmail.com>

lib/toolbox/SConscript

@@ -29,6 +29,7 @@ env.Append(
         File("stream/file_stream.h"),
         File("stream/string_stream.h"),
         File("stream/buffered_file_stream.h"),
+        File("strint.h"),
         File("protocols/protocol_dict.h"),
         File("pretty_format.h"),
         File("hex.h"),