Add "operator" option for fulltext query

[yangzq50]

What problem does this PR solve?

Add "operator" option for fulltext query

if add "operator=or" in query option:

• usual query syntax will not be considered
• all words in query string will be combined by "OR" operator and produce a query task

if add "operator=and" in query option:

• usual query syntax will not be considered
• all words in query string will be combined by "AND" operator and produce a query task

This option is useful if users want to use query strings like "A01-233:BC\等等"

Type of change

• New Feature (non-breaking change which adds functionality)
• Refactoring
• Test cases