ejabberd: Enable XEPs

According to https://github.com/iNPUTmice/ComplianceTester, the following XEPs are not enabled in our ejabberd configuration, but should be:

• XEP-0237: Roster Versioning (mod_roster)
• XEP-0313: Message Archive Management (mod_mam)
• XEP-0363: HTTP File Upload (mod_http_upload)
  • Add help text to explain implications of enabling.
  • Add a checkbox to enable/disable.
  • When enabled, configure mod_http_upload with default settings.
  • Configure mod_http_upload_quota with max_days=365, access_hard_quota=1.1GiB, access_soft_quota=1.0GiB.
  • Implement monitoring of storage used.
• XEP-0357: Push Notifications (mod_push)
• XEP-0065: SOCKS5 Bytestreams (mod_proxy65)