Feat/notification UI selection

[kiritowu]

Closes #203

Changes:

• Supabase migration to create book_subscription table
• Create backend APIs for CRUD operation on book_subscriptions table
• Add frontend UI and form to subscribe to different library for a particular book

desktop view (dialog)	mobile view (drawer)

[kiritowu]

Should i remove status and condition columns from database since they are not useful given our current usecase of daily morning email, or should i keep them for future-proof use case 🤔

[elliotwutingfeng]

I think we can drop the excess columns, we're still in beta and don't know what users prefer yet.

[elliotwutingfeng]

A "select all" for the libraries would be good too.