nixos/modules: Remove all usages of types.string

And replace them with a more appropriate type

Also fix up some minor module problems along the way

nixos/modules/services/logging/SystemdJournal2Gelf.nix

@@ -16,7 +16,7 @@ in
       };
 
       graylogServer = mkOption {
-        type = types.string;
+        type = types.str;
         example = "graylog2.example.com:11201";
         description = ''
           Host and port of your graylog2 input. This should be a GELF
@@ -25,7 +25,7 @@ in
       };
 
       extraOptions = mkOption {
-        type = types.string;
+        type = types.separatedString " ";
         default = "";
         description = ''
           Any extra flags to pass to SystemdJournal2Gelf. Note that
@@ -56,4 +56,4 @@ in
       };
     };
   };
-}
+}

nixos/modules/services/logging/awstats.nix

@@ -32,7 +32,7 @@ in
     };
 
     updateAt = mkOption {
-      type = types.nullOr types.string;
+      type = types.nullOr types.str;
       default = null;
       example = "hourly";
       description = ''
@@ -50,7 +50,7 @@ in
         description = ''Enable the awstats web service. This switches on httpd.'';
       };
       urlPrefix = mkOption {
-        type = types.string;
+        type = types.str;
         default = "/awstats";
         description = "The URL prefix under which the awstats service appears.";
       };

nixos/modules/services/logging/logcheck.nix

@@ -155,7 +155,7 @@ in
 
       config = mkOption {
         default = "FQDN=1";
-        type = types.string;
+        type = types.lines;
         description = ''
           Config options that you would like in logcheck.conf.
         '';

nixos/modules/services/logging/rsyslogd.nix

@@ -46,7 +46,7 @@ in
       };
 
       defaultConfig = mkOption {
-        type = types.string;
+        type = types.lines;
         default = defaultConf;
         description = ''
           The default <filename>syslog.conf</filename> file configures a
@@ -56,7 +56,7 @@ in
       };
 
       extraConfig = mkOption {
-        type = types.string;
+        type = types.lines;
         default = "";
         example = "news.* -/var/log/news";
         description = ''