MDL-44440 behat: Other fixes to make clean work properly

- Update the step to follow links inside a treeview
  to work also when JS is disabled.
- Make regions accept header and footer.
- Change some locators refering to non-clean compatible
  regions.
- Restricting click to the table row in forum tracking
  because seems to conflict with the navigation bar when
  using narrow window sizes.
MDL-44440 behat: Refactoring features to use I navigate to

Replacing multiple "I expand node" steps by the
new "I navigate to". Also fixing few I navigate to
when dealing with non-JS.