Implement EZP-23466: Elasticsearch language analysis

This PR resolves https://jira.ez.no/browse/EZP-23466

Initial idea was to use `_analyzer` mapping feature as described at http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/mapping-analyzer-field.html.
This would make the change minimal and would keep the language configuration out of the mapping.
However it does not work for nested documents, so different approach was required.

`meta_all` field is now replaced with `meta_all_*` per language code / locale. Analyzer is configured per `meta_all_*` field and is always named `analyzer_<language code>`, where hypen is replaced by an underline, for example `analyzer_cro_HR`. Separating `meta_all` also made necessary to provide fields that carry fulltext data separately.
Analyzer per language code does not mean that different analyzer must be used for each locale, which can be seen in `elasticsearch.yml`, where analyzer aliasing is used to configure same analyzer for different locales, where it makes sense.

Appropriate default analyzers are configured where possible, locales not having an analyzer among default ones are configured to `standard` analyzer. Configuration is provided for tests and as a starting point -- that is Elasticsearch domain and it will be user's responsibility to configure language analysis as they need (for example using plugins to configure analysis for languages not supported out of the box).

#### TODOs
- [x] Update Elasticsearch's specification