Add Cloudflare DNS support to Caddy configuration

- Updated .env.example to include CF_ZONE_READ and CF_DNS_EDIT variables.
- Enhanced Caddyfile to utilize Cloudflare DNS for TLS.
- Created Dockerfile for building Caddy with Cloudflare DNS support.
- Modified docker-compose.yml to use the new caddy-cloudflare image and set environment variables.

caddy/Dockerfile

@@ -0,0 +1,9 @@
+
+FROM caddy:2.10-builder AS builder
+
+RUN xcaddy build \
+  --with github.com/caddy-dns/cloudflare
+
+FROM caddy:2.10
+
+COPY --from=builder /usr/bin/caddy /usr/bin/caddy