[Spec] Support File blocks

[otoyo]

Definition

1. API endpoint is defined in src/pages/api/blocks/[id].ts
   • The endpoint is used for fetching the file URL(S3 signed URL) of the File blocks if the URL is expired
   • The endpoint allows GET /api/blocks/:id as a request
   • The endpoint returns JSON data of the block if the block type is 'file'
     • if the block type is not 'file', the endpoint respond 403 for security reasons
2. Component is defined in src/components/notion-blocks/File.astro
   • The component displays a download link to the file like Feature/Add the file block #51
   • The component make a request to the API to refresh the URL from front-end
   • The request is made IF...
     • the file URL is expired
     • the download link is clicked

Tips

• The download link element should have the expiry time in a data attribute like data-expiry-time="2023-02-13T..."

TODO

• Install adapter for Cloudflare worker
• Add an API endpoint as /api/blocks/[id].ts
• Define src/components/notion-blocks/File.astro

[otoyo]

Because downloading images to the local works well, I implemented file blocks also as the local download instead of the above.
#65