Move border custom css to Tailwind Class

- migrate custom css to Tailwind class
- introduce class-parameter for `AsImageElement`
- migrate width of login button to Tailwind class

UI/Base/Img.ts

@@ -4,16 +4,16 @@ import {Utils} from "../../Utils";
 export default class Img {
 
     public static runningFromConsole = false;
-    
+
    static AsData(source:string){
        if(Utils.runningFromConsole){
            return source;
        }
        return `data:image/svg+xml;base64,${(btoa(source))}`;
    }
-    
-    static AsImageElement(source: string): string{
-        return `<img src="${Img.AsData(source)}">`;
+
+    static AsImageElement(source: string, css_class: string): string{
+        return `<img class="${css_class}" alt="" src="${Img.AsData(source)}">`;
     }
 }