Add support of 1600 image size limit

Problem/Motivation

Users would like to fetch larger web-ready assets than the current max-limit of 1280.

Proposed resolution

Use API /ws/assets/<asset_id>/thumbnail to generate and fetch asset of 1600 size.

Remaining tasks

Currently while Drupal is requesting and processing the response from WebDam, the entity_browser widget does not show a wait-message, like a spinner or something. Therefore, there is a scope of improving the UX.

User interface changes

A new option 1600 will be available under Image size limit configuration.

API changes

A new API function will be available generateAssetThumbnail($asset_id, $width, $height) which will use the WebDam API <code>/ws/assets/<asset_id>/thumbnail. The new API will be able to generate asset of the provided size.

Data model changes

N/A