Support output attributes in the simplest case

Restrictions:

* simple format only
* no _subrecs support
* no expression support
Support complex format
Remove TODO done
Add a test case for output attribtues of subrecs
search: implement sub records output in simple mode
search: add a test case for sub records in complex
search: output attributes in subrecs at complex

Support attributes output for sub records in complex format
Extract SimpleAttributesFormatter
Extract ComplexAttributesFormatter
Switch formats by switching formatter
Remove redundant codes
Extract AttributeFormattable module
Extract RecordsFormatter
Use common logic to format a record
Use each instead of collect

each is enough for this case
Rename format to format_attributes
Use format_attributes to format sub attributes
Merge branch 'output-attributes'