[Identity] Add default attributes `keywords` & `description` for public data

[sunhuachuang]

Inspired by @DAOCUONG, he said: "data should support tags(use for index filter and discover the data)".

I think, non-public data does not need to be searched. Public data can be searched. So if add this default attributes, maybe good for data used.

[DAOCUONG]

User can use that field or not using it. This field is public and not encrypted

[sunhuachuang]

At present, can this field be associated with AI, by adding some tags, directly feed the data to ai