Extend the contao core search, to achieve more features like pdf search.

Don't worry, install via composer and all dependencies will be resolved like magic.

• [smalot/pdfparser] (https://github.com/smalot/pdfparser)

• index pdf files that are referenced inside searched pages and must be locally (contao filesystem) stored
• parse pdf files with smalot/pdfparser
• make usage of meta information from tl_files to provide better file titles (consider language too)
• group the results in the result list