[#1861] Add linter for FIXME and TODO.


Problem description
===================

Sometimes we forget to remove FIXME for current branch.

Other times we use TODO or a FIXME without a ticket.



Changes description
===================

Update to latest pocket lint and add custom expression for FIXME and TODO.


How to try and test the changes
===============================

reviewers @alibotean 

Let me know if you should catch other simple single line errors using regex.

Try to put wrong FIXME markers or a FIXME:current_ticket: in the code and run the linter.
It should prompt for errors.

Thanks!