feat: move acme certificate automation into a plugin (C7)

plugins/acme-ssl/CHANGELOG.md

@@ -0,0 +1,15 @@
+# Changelog
+
+## 1.0.0
+
+Bundled with Termix 2.9.0.
+
+- ACME certificates moved out of core. Termix no longer runs certbot; the
+  plugin talks to the CA directly.
+- The domain, email, challenge type and Cloudflare token moved from Admin
+  Settings into this plugin's settings. The token is now stored encrypted.
+- Renewal is automatic: a check every 12 hours renews within 30 days of
+  expiry.
+- The 2.8 certbot account is not reused. A new ACME account is registered on
+  the first request.
+- Uploading your own certificate stays in Admin Settings > HTTPS certificate.