Elasticsearch 8

Chnages from Elasticsearch 5

String vs. Text and Keyword Types not_analyzed

1. https://www.elastic.co/blog/strings-are-dead-long-live-strings
2. https://discuss.elastic.co/t/index-not-analyzed/126606

Removal of Mapping Types

1. https://www.elastic.co/guide/en/elasticsearch/reference/current/removal-of-types.html
2. https://www.elastic.co/guide/en/elasticsearch/reference/6.0/removal-of-types.html
3. https://www.elastic.co/blog/index-vs-type