Replace ingredient search function

[rolandgeider]

This now uses the existing filter mechanisms from django-filter.

Usage:

api/v2/ingredient/search?term=foo becomes api/v2/ingredient[info]/?name__search=foo&language__codes=en

Other changes:

• The old search filtered the results by language by default and used the special syntax &language=* to disable this filter. Now this behaviour can be controlled by passing the appropriate language parameter or not.
• The results are now paginated. Instead of having a fixed number of entries, more can be retrieved if needed. Also the page size can be specified like in the other endpoints with &limit=xyz
• All other filters can now be applied as well, such as &source_name=USDA