refactor to match current dokuwiki plugin style. Fix indentation.

[einhirn]

• Use of require_once spams deprecation logs.
• Fixed indentation
• updated to more current plugin style with class namespaces etc.
• removed the get_info() call so plugin.info.txt gets used.

[zaher]

Thank you @einhirn I merged without review , i am so far from DokuWiki and PHP now