Add health checks for Docker services, ACME environment readiness validation, and Certbot unit tests

- Introduced health checks to Docker Compose files for better service reliability.
- Added ACME environment readiness validation to ensure proper configuration for Certbot.
- Implemented unit tests for Certbot's `check_acme_environment_ready` method to cover edge cases.
- Improved E2E tests with startup wait adjustments and dynamic certificate issuance verification.
- Enhanced Kubernetes test cleanup with forced resource deletion for faster termination.

tests_e2e/docker/docker-compose-plugins-combined.yml

@@ -70,6 +70,12 @@ services:
       - /var/run/docker.sock:/var/run/docker.sock
       - ./cloudflare_ips.lst:/etc/easyhaproxy/cloudflare_ips.lst:ro
       - ./jwt_pubkey.pem:/etc/easyhaproxy/jwt_keys/api_pubkey.pem:ro
+    healthcheck:
+      test: ["CMD", "curl", "-f", "-u", "admin:password", "http://localhost:1936"]
+      interval: 10s
+      timeout: 5s
+      start_period: 30s
+      retries: 3
     environment:
       EASYHAPROXY_DISCOVER: docker
       HAPROXY_CUSTOMERRORS: "true"