Refactor slideshow.js

[heyhippari]

Changes

Refactors slideshow.js to use standard features of Swiper where applicable.

• Now uses virtual slides, only loading three items at a time (Current, previous and next), and preloads images (Better memory usage and performance for large libraries, as well as nicer experience).
• Handle previous/next keyboard navigation using Swiper itself
• Support play and pause keyboard inputs
• Use the full resolution image
• Disable autoplay by default except on Chromecast
• Use Swiper itself to bind events to the next/previous arrows
• Remove dead code and useless cruft

As a result of using virtual slides, looping had to be disabled.

Issues

Fixes #915
Fixes #918

[nielsvanvelzen]

Related feature request

[dmitrylyzo]

In TV layout, left/right keys move focus and switch slides simultaneously.

Not related
Dialogs are broken when you use browser's Back. After switch to new page.js, dialogs do not use history.

[JustAMan]

YOLO

[dmitrylyzo]

Loop is somehow works, but first slide moves from left to right.

Edit:
in autoplay mode only

[ghost]

I know this has been closed issue. However, during the refactoring of the code we forgot to do one important thing. Give end User ability to change slideshow timing. Its currently 3000ms. This is way, way too short. Can we make it User programable? Part fo the settings or config? This is way overdue.