Add the ability to add notes to any post + add categories to post + hide posts\categories

Additional facts: 1) The code is pretty ugly and break multiple good programming principles. Take care of your eyes. 2) The script saves notes to a local storage. It is not optimized. 3) It have no backup support for now, do not use it to store an important information. 4) It partially uses es6 features (not in the best way), so ensure that your browser is supporting it.

Have fun!