feat: Move to passport for authentication (#1934)

- Added `accountProvisioner`
- Move authentication to use passport strategies
- Make authentication more pluggable
- Change language of services -> providers

closes #1120

server/utils/fs.js

@@ -0,0 +1,22 @@
+// @flow
+import path from "path";
+import fs from "fs-extra";
+
+export function requireDirectory<T>(dirName: string): [T, string][] {
+  return fs
+    .readdirSync(dirName)
+    .filter(
+      (file) =>
+        file.indexOf(".") !== 0 &&
+        file.endsWith(".js") &&
+        file !== path.basename(__filename) &&
+        !file.includes(".test")
+    )
+    .map((fileName) => {
+      const filePath = path.join(dirName, fileName);
+      const name = path.basename(filePath.replace(/\.js$/, ""));
+
+      // $FlowIssue
+      return [require(filePath), name];
+    });
+}