* Clean up after V2 migration This PR removes all the leftovers and alternative code branching after v2 migration. The self-hosted release is being drafted at: https://github.com/plausible/hosting/issues/68 Refs: - https://github.com/plausible/analytics/pull/2865 - https://github.com/plausible/analytics/pull/2825 - https://github.com/plausible/analytics/pull/2780 * !fixup