Add drag and drop in library component

[digitalethics]

It would be great to be able to position book covers in any order in the library component (drag & drop) to better resemble the freedom one has with an analogue bookshelf.¹

¹Could you add a library label here in GitHub to better track all related (and upcoming) issues?

[digitalethics]

The ability to drag files into the library window to automatically open them would also be very convenient.

[BlazarKnight]

@digitalethics I want this feature to do you want to work on a pull request with me?

[BlazarKnight]

we could probably use this bit of code from https://github.com/johnfactotum/foliate-js/blob/052123beafed921a9a2a45ef6330c235289a634e/reader.js

const dragOverHandler = e => e.preventDefault()
const dropHandler = e => {
    e.preventDefault()
    const item = Array.from(e.dataTransfer.items)
        .find(item => item.kind === 'file')
    if (item) {
        const entry = item.webkitGetAsEntry()
        open(entry.isFile ? item.getAsFile() : entry).catch(e => console.error(e))
    }