search: loading of Bloodhound using requirejs

Twitter's typeahead exports also Bloodhound their data fetching engine. It is a missing part of the current configuration. However everything works in the current pu because loading of 'typeahead' dependency stores `Bloodhound` class in the global namespace anyway. This PR makes possible loading Bloodhound in a proper requirejs way.

I haven't modify here the deposit module because it uses custom data fetching.
Q: do we need the extra spaces inside object?
```javascript
typeahead: { deps: ['jquery'], exports: 'Bloodhound' },
```
*vs*
```javascript
typeahead: {deps: ['jquery'], exports: 'Bloodhound'},
```