UPDATE: split the webapp in a widget and the app itself

This splits the webapp in:

* IronCalc (the widget to be published on npmjs)
* The frontend for our "service"
* Adds "dummy code" for the backend using sqlite

webapp/app.ironcalc.com/frontend/src/components/ShareButton.tsx

@@ -0,0 +1,30 @@
+import styled from "@emotion/styled";
+import { Share2 } from "lucide-react";
+
+export function ShareButton(properties: { onClick: () => void }) {
+  const { onClick } = properties;
+  return (
+    <Wrapper onClick={onClick} onKeyDown={() => {}}>
+      <Share2 style={{ width: "16px", height: "16px", marginRight: "10px" }} />
+      <span>Share</span>
+    </Wrapper>
+  );
+}
+
+const Wrapper = styled("div")`
+  cursor: pointer;
+  color: #ffffff;
+  background: #f2994a;
+  padding: 0px 10px;
+  height: 36px;
+  line-height: 36px;
+  border-radius: 4px;
+  margin-right: 10px;
+  display: flex;
+  align-items: center;
+  font-family: "Inter";
+  font-size: 14px;
+  &:hover {
+    background: #d68742;
+  }
+`;