impl kb_info & dialog_info & doc_info (#9)

Cargo.toml

migration/src/m20220101_000001_create_table.rs

src/api/dialog_info.rs

src/api/doc_info.rs

src/api/kb_info.rs

src/api/mod.rs

src/entity/doc_info.rs

src/entity/mod.rs

src/service/dialog_info.rs

src/service/doc_info.rs

src/service/kb_info.rs

src/service/mod.rs

src/service/tag_info.rs