fix(signup): signup auth (#15628)

* fix(models.user): Colocate all user methods

Moved user methods/extensions into one file. Tracked down `next method
called more than once` error and setting headers after their sent. Let
regular error handler handle api errors as well.

* feat(server.auth): Disable github account creation

We are no longer allowing account creation through github

* refactor(Auth): Move user identity link into models dir

* feat(Disable link account login): This removes the ability to use a linked account t

* feat(errorhandlers): Add opbeat, filter out handled error

server/middlewares/error-reporter.js

@@ -0,0 +1,30 @@
+import opbeat from 'opbeat';
+import debug from 'debug';
+
+import {
+  isHandledError,
+  unwrapHandledError
+} from '../utils/create-handled-error.js';
+
+const log = debug('fcc:middlewares:error-reporter');
+
+export default function keymetrics() {
+  if (process.env.NODE_ENV !== 'production') {
+    return (err, req, res, next) => {
+      if (isHandledError(err)) {
+        // log out user messages in development
+        const handled = unwrapHandledError(err);
+        log(handled.message);
+      }
+      next(err);
+     };
+  }
+  return (err, req, res, next) => {
+    // handled errors do not need to be reported
+    // the report a message and redirect the user
+    if (isHandledError(err)) {
+      return next(err);
+    }
+    return opbeat.captureError(err, { request: req }, () => next(err));
+  };
+}