Add accessibility features including button and panel

- Introduced an accessibility button that toggles a panel with options.
- Implemented high contrast mode toggle functionality.
- Added CSS styles for accessibility button and panel.
- Created JavaScript to manage accessibility features and local storage for user preferences.
- Included necessary CSS and JS files in the theme's head template.

themes/InterBlue/assets/css/accessibility.scss

@@ -0,0 +1,66 @@
+#accessibility-button {
+  position: fixed;
+  bottom: 20px;
+  right: 20px;
+  background: #6366f1;
+  color: white;
+  border-radius: 50%;
+  width: 50px;
+  height: 50px;
+  font-size: 24px;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  cursor: pointer;
+  z-index: 9999;
+  box-shadow: 0 0 10px rgba(0, 0, 0, 0.2);
+}
+
+#accessibility-panel {
+  position: fixed;
+  top: 0;
+  right: 0;
+  width: 280px;
+  height: 100%;
+  background: #f9f9f9;
+  box-shadow: -2px 0 10px rgba(0, 0, 0, 0.1);
+  transform: translateX(100%);
+  transition: transform 0.3s ease;
+  z-index: 9998;
+  display: flex;
+  flex-direction: column;
+
+  #close-accessibility-panel {
+    border: 0;
+    height: 30px;
+    width: 30px;
+    border-radius: 6px;
+  }
+}
+
+#accessibility-panel.open {
+  transform: translateX(0);
+}
+
+.panel-header {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  background: #6366f1;
+  color: white;
+  padding: 1rem;
+  font-weight: bold;
+}
+
+.panel-body {
+  padding: 1rem;
+  display: flex;
+  flex-direction: column;
+  gap: 10px;
+}
+
+#toggle-contrast {
+  padding: 10px;
+  font-size: 16px;
+  cursor: pointer;
+}