fix: add 'CONTAIN' support in query builder

[yangyangv2]

This fix to address the issue #114

Checklist

• The PR conforms to DataHub's Contributing Guideline (particularly Commit Message Format)
• Links to related issues (if applicable)
• Tests for the changes have been added/updated (if applicable)
• Docs related to the changes have been added/updated (if applicable)

[keremsahin1]

There seems to be something off here. Why do I see diff from @kaliang1 in this PR?

[camelliazhang]

also, the current query template supports advanced query as well, so that user can just issue *text? https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-query-string-query.html

[yangyangv2]

also, the current query template supports advanced query as well, so that user can just issue *text? https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-query-string-query.html

Good to know! It could be good for advance users.

This specific ask is for supporting CONTAIN with sbustring query, we prefer to have explicit filter options (CONTAIN, START_WITH, END_WITH) to users and hide ES internal details such as ''. If users knows they are looking for START_WITH, then using START_WITH will perform better as the underlying query pattern is _wildcard_query(term)_.

Exposing * to users may lead to complexity and out of controlled use cases such as searching on "ABCD*"..etc.

[yangyangv2]

also, the current query template supports advanced query as well, so that user can just issue *text? https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-query-string-query.html