Site URL and image enhancements

Included in this release:

• SiteURL Processor: Added setParamsCallback() to adjust the URL parameters on the fly.
• SiteURL Processor: Now sorting URL parameters alphabetically for consistent URLs.
• Image Processor: Added the height, id and alt attributes to the image command.
• Image Processor: Added docs in the README for the image command.

Added raw HTML support

Included in this release:

• Processors: The HTML processor can add raw HTML code.
• Renderer: Added isValid() and getResults() to check for processor errors.
• Renderer: Fixed a return type doc for PHPStan chaining detection.

Added site URLs

Included in this release:

• Processors: Added the handling of website-internal links.

Initial release

Included in this release:

• Base rendering system.
• Bundled image command.
• Bundled video command.