add front end code (#27)

web/src/layouts/index.tsx

web/src/locales/config.ts

web/src/locales/en.json

web/src/locales/zh.json

web/src/pages/404.jsx

...-knowledge/components/knowledge-file/createEFileModal.tsx

.../pages/add-knowledge/components/knowledge-file/index.less

...c/pages/add-knowledge/components/knowledge-file/index.tsx

...rc/pages/add-knowledge/components/knowledge-file/model.ts

...d-knowledge/components/knowledge-file/segmentSetModal.tsx

.../pages/add-knowledge/components/knowledge-file/upload.tsx

...pages/add-knowledge/components/knowledge-search/index.tsx

...ges/add-knowledge/components/knowledge-setting/index.less

...ages/add-knowledge/components/knowledge-setting/index.tsx

...pages/add-knowledge/components/knowledge-setting/model.ts

web/src/pages/add-knowledge/index.less

web/src/pages/add-knowledge/index.tsx

web/src/pages/add-knowledge/model.ts

web/src/pages/chat/index.tsx

web/src/pages/chat/model.ts