Move spotify proxy alongside website

That's all it's really used for right now.

ansible/roles/website/vars/main.yml

@@ -1,5 +1,6 @@
-spotify_proxy_host: "{{ vault_spotify_proxy_host }}"
 website_secret_key: "{{ vault_website_secret_key }}"
 website_sentry_dsn: "{{ vault_website_sentry_dsn }}"
 unsplash_client_id: "{{ vault_unsplash_client_id }}"
-website_basic_auth: "{{ vault_website_basic_auth }}"
+spotify_client_id: "{{ vault_spotify_client_id }}"
+spotify_client_secret: "{{ vault_spotify_client_secret }}"
+spotify_sentry_dsn: "{{ vault_spotify_sentry_dsn }}"