Removing MooTools dependencies form media/com_finder/js/indexer.js and removing unused JS

Under GSoC MooTools to jQuery project, this PR removes the MooTools dependencies in media/com_finder/js/indexer.js file and removing hilighter.js and finder.js which is not used within the CMS.

Note:
Removal of MooTools dependencies from autocompleter.js and slidercompleter.js is not included due to their higher complexity, which requires to find alternative libraries to replace them.