feat: File attachments (#3031)

* stash

* refactor, working in non-collab + collab editor

* attachment styling

* Avoid crypto require in browser

* AttachmentIcon, handling unknown types

* Do not allow attachment creation for file sizes over limit

* Allow image as file attachment

* Upload placeholder styling

* lint

* Refactor: Do not use placeholder for file attachmentuploads

* Add loading spinner

* fix: Extra paragraphs around attachments on insert

* Bump editor

* fix build error

* Remove attachment placeholder when upload fails

* Remove unused styles

* fix: Attachments on shared pages

* Merge fixes

shared/utils/files.ts

@@ -0,0 +1,21 @@
+/**
+ * Converts bytes to human readable string for display
+ *
+ * @param bytes filesize in bytes
+ * @returns Human readable filesize as a string
+ */
+export const bytesToHumanReadable = (bytes: number) => {
+  const out = ("0".repeat((bytes.toString().length * 2) % 3) + bytes).match(
+    /.{3}/g
+  );
+
+  if (!out || bytes < 1000) {
+    return bytes + " Bytes";
+  }
+
+  const f = out[1].substring(0, 2);
+
+  return `${Number(out[0])}${f === "00" ? "" : `.${f}`} ${
+    "  kMGTPEZY"[out.length]
+  }B`;
+};