Align rendering with ShortCode Image with the of Image in SS template

[maxime-rainville]

As a developer I want the ability to customize the rendering of images.

Acceptance criteria

• Images generated via shortcode use the same rendering logic as images rendered in SS templates.
• Developers can customise how images are rendered by providing a custom SS file in their theme.
• Common <img> tag attributes have alias on ImageManipulation
• Sensible extension hooks are added to the image rendering logic.
• The developer docs provides clear guidance on how to output images in their templates.
• The developer docs provides clear guidance on how to customise the Image rendering template.
• images in emails are still appropriately rendered even for older email clients