Bazaar-backend: Add user entity field to members table

A new field has been added to the members table. When a user has
requested to be added to a project the "identityApi" is used to get the
entity ref of the user.

Signed-off-by: Niklas Aronsson <niklasar@axis.com>

.changeset/tough-seahorses-learn.md

@@ -0,0 +1,26 @@
+---
+'@backstage/plugin-bazaar-backend': minor
+---
+
+**BREAKING** The bazaar-backend createRouter now requires that the `identityApi` is passed to the router.
+
+These changes are **required** to `packages/backend/src/plugins/bazaar.ts`
+
+The user entity ref is now added to the members table and is taken from the requesting user using the `identityApi`.
+
+```diff
+import { PluginEnvironment } from '../types';
+import { createRouter } from '@backstage/plugin-bazaar-backend';
+import { Router } from 'express';
+
+export default async function createPlugin(
+  env: PluginEnvironment,
+): Promise<Router> {
+  return await createRouter({
+    logger: env.logger,
+    config: env.config,
+    database: env.database,
++   identity: env.identity,
+  });
+}
+```