apache-frontend: Use custom global certificates for apache frontend

software/apache-frontend/instance.cfg

@@ -83,6 +83,8 @@ configuration.plain_http_port = 8080
 configuration.server-admin = admin@example.com
 configuration.apache_custom_https = ""
 configuration.apache_custom_http = ""
+configuration.apache-key =
+configuration.apache-certificate =
 configuration.open-port = 80 443
 
 [jinja2-template-base]
@@ -315,6 +317,8 @@ key-file = $${cadirectory:certs}/apache_frontend.key
 cert-file = $${cadirectory:certs}/apache_frontend.crt
 executable = $${directory:service}/frontend_apache
 wrapper = $${directory:service}/frontend_apache
+key-content = $${instance-parameter:configuration.apache-key}
+cert-content = $${instance-parameter:configuration.apache-certificate}
 # Put domain name
 name = $${instance-parameter:configuration.domain}