feat: Support importing .docx or .html files as new documents (#1551)

* Support importing .docx as new documents

* Add html file support, build types and interface for easily adding file types to importer

* fix: Upload embedded images in docx to storage

* refactor: Bulk of logic to command

* refactor: Do all importing on server, so we're not splitting logic for import into two places

* test: Add documentImporter tests


Co-authored-by: Lance Whatley <whatl3y@gmail.com>

server/utils/dataURItoBuffer.js

@@ -0,0 +1,20 @@
+// @flow
+
+export default function dataURItoBuffer(dataURI: string) {
+  const split = dataURI.split(",");
+
+  if (!dataURI.startsWith("data") || split.length <= 1) {
+    throw new Error("Not a dataURI");
+  }
+
+  // separate out the mime component
+  const type = split[0].split(":")[1].split(";")[0];
+
+  // convert base64 to buffer
+  const buffer = Buffer.from(split[1], "base64");
+
+  return {
+    buffer,
+    type,
+  };
+}