net/haproxy: support an unlimited number of SSL certificates

[fraenki]

A user reported that HAProxy has issues when using a large number of SSL certificates. Apparently there's a limit for maximum line length in HAProxy's configuration file according to the startup message:

[ALERT] line too long, truncating at word 65, position 1310

My patch addresses this issue by replacing crt with crt-list in HAProxy's configuration file. Our certificate exporter now creates *.crtlist files in /var/etc/haproxy/ssl/ that may contain an arbitrary number of certificate entries.

diff old vs. new configuration:

 frontend testing_frontend_ssl
-    bind opnsense-test:8443 name opnsense-test:8443 ssl crt /var/etc/haproxy/ssl/57026cd2482fa.pem crt /var/etc/haproxy/ssl/56eabc82e75ba.pem crt /var/etc/haproxy/ssl/595a40a38f0c5.pem
+    bind opnsense-test:8443 name opnsense-test:8443 ssl crt-list /var/etc/haproxy/ssl/5714b2452e6519.03813028.crtlist 

[fraenki]

Approved by the reporter :)

[fichtner]

@fraenki to the rescue, thanks!