Refactored add_block.html.twig - fixed CS and bugs

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #2312, #2248, #2277
| License       | MIT

This PR fixes these issues with add_block.html twig template (it renders the top right menu with links for quicker move to create form of admins):
 -  fixed Twig CS
 - invalid html tags (`ul` replaced with `div`, because `div` cannot be child of `ul`)
 - fixed checking wrong LIST permission instead of CREATE when counting items of group
 - fixed overflowing too long texts out of the menu (wrongly closed html tags), 
 - fixed counting of columns (avoid empty column if no group is available)
 - fixed not displaying group that does not have any item