Added TypeScript for frontend

Added type definitions for components, functions, data
Added guards for network responses
fixes #8

front/src/hooks/api/index.ts

@@ -0,0 +1,5 @@
+export { default as useHomeAnnouncementList } from './useHomeAnnouncementList'
+export { default as useBook } from './useBook'
+export { default as useAuth } from './useAuth'
+export { default as useTrashboxes } from './useTrashboxes'
+export { default as useAddAnnouncement } from './useAddAnnouncement'