feat: use input element directly

Previously, a button proxy was used which required the use of complicated reference management. Using the HTML `input` element directly simplifies the implementation.

Also moved some styles.

ref: N25B-189

src/pages/VisProgPage/VisProg.module.css

@@ -26,14 +26,6 @@
     align-items: center;
 }
 
-.save-load-panel {
-    outline: 2.5pt solid black;
-    border-radius: 0 0 5pt 5pt;
-    border-color: dimgrey;
-    background-color: canvas;
-    align-items: center;
-}
-
 .dnd-node-container {
     background-color: canvas;
     justify-content: center;
@@ -134,23 +126,3 @@
     outline: red solid 2pt;
     filter: drop-shadow(0 0 0.25rem red);
 }
-
-.save-button-like {
-    padding: 3px 10px;
-    background-color: canvas;
-    border-radius: 5pt;
-    outline: dodgerblue solid 2pt;
-    filter: drop-shadow(0 0 0.25rem dodgerblue);
-}
-
-a.save-button-like {
-    display: inline-block;       
-    text-decoration: none;      
-    color: inherit;              
-    cursor: pointer;            
-    transition: filter 200ms, background-color 200ms;
-}
-
-a.save-button-like:hover {
-    filter: drop-shadow(0 0 0.5rem dodgerblue);
-}