Provide possibility to customize analyzer/tokenyzer for Elasticsearch

[vkublytskyi]

Magento 2 has hardcoded Elasticsearch analyzer/tokenyzer. Existing implementation should be extended to provide a possibility to change analyzer/tokenyzer. At primitive implementation, it may be argument passed by DI. Also possible implementation is to provide possibility to choose analyzer/tokenyze from admin config panel per store view. More suitable solution will be to pick correct analyzer/tokenyzer based on store locale and provide possibility to other modules register their implementation of choosing valid analyzer/tokenyzer.

Any of listed solution is valid and it is up to developer which path to follow.

[HirokazuNishi]

Development branch is here:
https://github.com/Veriteworks/magento2-l10n/tree/improve-elasticsearch