Stable v2.10.81

Features

• Add mail checkbox to on-demand site backup
• Add per-row PHP version switch in PHPVersionSitesModal

Improvements

• Read document_root fresh from DB for single-site PHP switch
• Check both envelope and header From for rspamd blacklist rules
• Add Reseller-Pläne and Onboarding-Assistent admin pages
• Deep-links into the site list used ?exp= instead of ?expand=
• Don't commit a partial measurement as if it were complete
• Measure each site via its own server, not the subscription's
• Close audit gaps for isolation-repair, bayes, upstream-antispam, relay password