Set custom class name for active li element

Add ability to set custom class name for active "li" element in menu.
Example:
echo $this->navigation('navigation')->menu()
     ->setUlClass('uk-navbar-nav uk-hidden-small')
     ->setLiActiveClass('uk-active')
     ->setMaxDepth(0)
     ->setRenderInvisible(false);
Create css2.html for test LiActiveClass method
Add test for munu liActiveClass method
Add missed getLiActiveClass() method
Add liActiveClass using recommendations
fix copy-paste error
Move new variable to end of the list
Drop spaces
Merge pull request #5650 from sopinorg/patch-1

Set custom class name for active li element
[#5650] CS fixes

- trailing whitespace
- s/@return Menu/@return self/ throughout
[#5650] Test fix

- including test asset files often results in additional whitespace at
  end of string; updated assertion to trim() first.
Merge branch 'feature/5650' into develop

Close #5650