Request validation & custom diagram config

[coma007]

I added custom configuration of diagram which can be added as additional parameter by calling MermaidScope.transform function or in constructor of MermaidScope.

Also, this time request is verified with parse function from repos\kaleido\js\parse.js.

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I encountered following problems that I may resolve in some future PRs:

• Handling different versions of Mermaid API: I am not sure how can I extract the current version from the mermaid object, which makes limitations in implementing different render flow for different versions.
• Adding different image formats: For now, svg is supported only. While trying to add other image formats, unexpected behavior happened during conversions using this code (probably because the script is run in headless mode, so the image never loads):

function convertSVGToImageBytes(svg, format = 'image/png') {
    return new Promise((resolve, reject) => {
       
        const image = document.createElement("img")
        image.onload = () => {
            const canvas = document.createElement('canvas');
            canvas.width = image.width;
            canvas.height = image.height;
            const ctx = canvas.getContext('2d');
            ctx.drawImage(image, 0, 0);
            const imageData = canvas.toDataURL(format);
            resolve(imageData);
      };
     
      image.onerror = (e) => reject(e);
     
      image.src = 'data:image/svg+xml;base64,' + btoa(svg);
    });
  }

[mandic-bojana]

Left only one comment :)