Extend UI for Cancel Membership view

[lukasbuenger]

Depends on https://github.com/orbiting/backends/pull/132.

• Query, display and ask for cancellation category when cancelling a membership.
• Allow (re)activation of memberships with !new instead of !active.
• Display membership cancellations in User details.
• Display àutoPay` on membership details
• Add option to suppress subsequent email notifications to cancel membership UI.
• Fix missing reducedPrice prop query
• Add link to membership ui: env.REPUBLIK_FRONTEND_URL + '/angebote?package=PROLONG&token=' + user.accessToken