haproxy: Update HAProxy to v2.0.0 (LTS)

- Update haproxy download URL and hash
- Add new patches
- Add several CFLAGS (derived from haproxy Makefile) to make the build work with v1.9+
- Update default configuration
- Add check-command (for config) to init-script
- Add prometheus-service from contribs by default

Signed-off-by: Christian Lachner <gladiac@gmail.com>

net/haproxy/files/haproxy.cfg

@@ -1,6 +1,6 @@
-# Example configuration file for HAProxy 1.3, refer to the url below for
+# Example configuration file for HAProxy 2.0, refer to the url below for
 # a full documentation and examples for configuration:
-# http://haproxy.1wt.eu/download/1.3/doc/configuration.txt
+# https://cbonte.github.io/haproxy-dconv/2.0/configuration.html
 
 
 # Global parameters
@@ -38,6 +38,13 @@ global
 	# limits like number of open file descriptors. Default is 1.
 	#nbproc 2
 
+# Default parameters
+defaults
+	# Default timeouts
+	timeout connect 5000ms
+	timeout client 50000ms
+	timeout server 50000ms
+
 
 # Example HTTP proxy listener
 listen my_http_proxy
@@ -78,9 +85,9 @@ listen my_smtp_proxy
 	# Round robin load balancing over two servers on port 123 forcing
 	# the address 192.168.1.1 and port 25 as source.
 	balance roundrobin
-  #use next line for transparent proxy, so the servers can see the 
-  #original ip-address and remove source keyword in server definition
-  #source 0.0.0.0 usesrc clientip
+	#use next line for transparent proxy, so the servers can see the 
+	#original ip-address and remove source keyword in server definition
+	#source 0.0.0.0 usesrc clientip
 	server server01 192.168.1.10:123 source 192.168.1.1:25
 	server server02 192.168.1.20:123 source 192.168.1.1:25