Style ever-slider active states, permanent arrows and remove dots

[CySSoO]

Motivation

• Provide premium e-commerce visual finishing for the Everblock slider so the center slide is sharp and lateral slides are gently attenuated.
• Keep existing slider logic and layout intact while exposing a simple is-active / is-inactive state to drive visuals.

Description

• Add CSS rules in views/css/everblock.css introducing .ever-slider-item, .ever-slider-item.is-active and .ever-slider-item.is-inactive for smooth opacity/filter transitions and permanent directional arrow styling for .ever-slider-prev and .ever-slider-next.
• Remove dot-related styling and pagination visual clutter and ensure arrow buttons are position:absolute, centered vertically and above images (z-index).
• Update views/js/everblock-slider.js to remove dot generation/management and add updateItemStates(state) which toggles is-active/is-inactive on items, and call it from updateState and goToIndex without changing layout calculations.
• Remove the dots container from the template views/templates/hook/prettyblocks/prettyblock_img.tpl so no pagination elements remain in the DOM.

Testing

• No automated tests were executed for this change.

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Codex Task