process_alias_urltable: Added data validation

I had noticed that if the downloaded file had unexpected data(In my case a simple <br> tag) that pf would stop functioning properly. I have added data validation and tested various entries. Skipped entries are logged to the system log. 

Test results below:

192.168.1.100		 			|| OK
2607:f0d0:1002:51::4				|| OK
192.168.256.100		 		|| SKIPPED
2607:x0d0:1002:51::4			 	|| SKIPPED

192.168.1.0/24		 			|| OK
2001:1234::5678:5:6:7:8/64			|| OK
192.168.1x.0/24					|| SKIPPED
2001:1234::x678:5:6:7:8/64			|| SKIPPED

!192.168.1.100		 			|| OK
!2607:f0d0:1002:51::4		 		|| OK
!192.168.256.100		 		|| SKIPPED
!2607:x0d0:1002:51::4			|| SKIPPED

!192.168.1.0/24		 			|| OK
!2001:1234::5678:5:6:7:8/64		|| OK
!192.168.1x.0/24				|| SKIPPED
!2001:1234::x678:5:6:7:8/64		|| SKIPPED

192.168.1.0/24 #test		 		|| OK (Rewritten as 192.168.1.0/24)
192.168.1.0/24 ;test		 		|| OK (Rewritten as 192.168.1.0/24)
!192.168.1.0/24 #test		 		|| OK (Rewritten as !192.168.1.0/24)
!192.168.1.0/24 ;test		 		|| OK (Rewritten as !192.168.1.0/24)

123.123.123.0/24\n				|| OK (Rewritten as 123.123.123.0/24)
123.123.123.0/24<br>				|| OK (Rewritten as 123.123.123.0/24)
123.123.123.0/24<br/>			|| OK (Rewritten as 123.123.123.0/24)
123.123.123.0/24<br />			|| OK (Rewritten as 123.123.123.0/24)

####comment_test				|| SKIPPED
 ## ##comment_test				|| SKIPPED
#comment_test					|| SKIPPED
# comment_test					|| SKIPPED
 # comment_test				|| SKIPPED
#!11.11.1.0/24 #test				|| SKIPPED

Error establishing DB connection		|| SKIPPED
br<br>		 				|| SKIPPED

/***************** BELOW IS FOR "urltable_ports" WHEN SUPPORTED *****************/
80		 				|| OK
443						|| OK
!21						|| OK
8080:8082					|| OK
8080-8082					|| OK (Rewritten as 8080:8082)
!8080:8082				|| OK
!8080-8082				|| OK (Rewritten as !8080:8082)
8080 : 8082				|| OK (Rewritten as 8080:8082)
8080 - 8082				|| OK (Rewritten as 8080:8082)
8080,8081,8082				|| SKIPPED

8000 #test					|| OK (Rewritten as 8000)
8001 ;test					|| OK (Rewritten as 8001)
!8000 #test				|| OK (Rewritten as !8000)
!8001 ;test					|| OK (Rewritten as !8001)

1234\n					|| OK
1234<br>					|| OK (Rewritten to 1234\n)
1234<br/>					|| OK (Rewritten to 1234\n)
1234<br />					|| OK (Rewritten to 1234\n)