added search indexing class for indexing basic activity information (…

[iceripple]

indexes common module data (name and intro)
see https://docs.moodle.org/dev/Search_API#Easy_case:_Activity_information

(cherry picked from commit 6819a46)

[iceripple]

new pull request in response to #275

[thomasmars]

Thanks for the pull request. I've created an issue for reviewing and merging it in through our public issue tracker: https://h5ptechnology.atlassian.net/browse/HFP-2811.
I'll try to get it included on the next Moodle release if it passes review.

[thomasmars]

getting the following error when running cron with these changes:

++ Invalid get_string() identifier: 'search:activity' or component 'mod_hvp'. Perhaps you are missing $string['search:activity'] = ''; in mod/hvp/lang/en/hvp.php? ++
* line 353 of /lib/classes/string_manager_standard.php: call to debugging()
* line 7289 of /lib/moodlelib.php: call to core_string_manager_standard->get_string()
* line 146 of /search/classes/base.php: call to get_string()
* line 1104 of /search/classes/manager.php: call to core_search\base->get_visible_name()
* line 59 of /lib/classes/task/search_index_task.php: call to core_search\manager->index()
* line 189 of /lib/cronlib.php: call to core\task\search_index_task->execute()
* line 114 of /lib/cronlib.php: call to cron_run_inner_scheduled_task()
* line 73 of /lib/cronlib.php: call to cron_run_scheduled_tasks()
* line 81 of /admin/cron.php: call to cron_run()
Processing area: [[search:activity]]

This must be fixed before this can be merged in