Add support for legacy relays API

central_frontend/src/widgets/CopyToClipboard.tsx

@@ -0,0 +1,30 @@
+import { ButtonBase } from "@mui/material";
+import { PropsWithChildren } from "react";
+import { useSnackbar } from "../hooks/context_providers/SnackbarProvider";
+
+export function CopyToClipboard(
+  p: PropsWithChildren<{ content: string }>
+): React.ReactElement {
+  const snackbar = useSnackbar();
+
+  const copy = () => {
+    navigator.clipboard.writeText(p.content);
+    snackbar(`${p.content} copied to clipboard.`);
+  };
+
+  return (
+    <ButtonBase
+      onClick={copy}
+      style={{
+        display: "inline-block",
+        alignItems: "unset",
+        textAlign: "unset",
+        position: "relative",
+        padding: "0px",
+      }}
+      disableRipple
+    >
+      {p.children}
+    </ButtonBase>
+  );
+}