Add Kindle-friendly browser interface

[carderne]

Relevant issues

• https://github.com/janeczku/calibre-web/issues/2723

Background

It would be great to be able to use calibre-web from a Kindle and directly download books. My current flow is to use calibre-web to manage/explore books, and then a separate process to get the book onto the Kindle.

Description

This PR adds two new routes:

• /basic?query=<term>: equivalent of /search
• /basic_book/<id>: equivalent of /book/<id>

They have no CSS or JavaScript and very basic structure. This is aimed at creating a page that the Kindle web browser can easily handle.

The only features that are maintained:

• login (this page is unchanged)
• logout from every page
• simple search
• book list with <authors> - <title>
• book detail view with download links

Comments

I went as basic as possible to create a small diff, demonstrate the purpose, and create a tiny maintenance surface area if this gets merged.

Some functionality could be added back, but it's a trade-off with the limited browser. Search, select and download is all I need, but others may have different requirements.

Obviously happy to implement this in a different way if you think preferable!

Screenshots

Search page, after searching

Book detail page