server7: remove missing collectd plugins

Something happened to collectd between 19.09 and 20.03

hosts/server7/default.nix

@@ -130,16 +130,11 @@ in {
   ];
 
   services.collectd.extraConfig = ''
-    LoadPlugin sensors
     LoadPlugin memory
-    LoadPlugin irq
-    LoadPlugin thermal
     LoadPlugin processes
     LoadPlugin disk
-    LoadPlugin hddtemp
     LoadPlugin df
     LoadPlugin cpu
-    LoadPlugin cpufreq
     LoadPlugin entropy
     LoadPlugin load
     LoadPlugin swap