Update hooks page
Created by: mickadoo
General cleanup and restructuring of the hooks page. I moved the joomla! and drupal setup to separate pages because I think it was long enough already. I haven't updated these pages, just pasted them as they are.
- add .gitignore file
- move framework-specific stuff to separate file (drupal and joomla! setup)
- update overview
- add tips and warnings to make it look nicer
- add section on hook naming since I think that this is something newbies need to know first
- replace long code blocks (that focus more on other components) with simpler blocks that show hook usage only.
- replace validate with validateForm because I don't see validate in the latest version
- remove complicated example for setting custom values
- update tokenValues function to match newer version (which I took from the core master branch)
- remove examples of executing raw SQL
- remove h1 and change to title for overview section as page title as h1 is automatically inserted
- remove unecessary asterisks