NEW API: sysadm/iocage "action"="cleantemplates"

This will delete all templates which have been cached on the local system.
-----------

REST Request (example):
-------------------------------
PUT /sysadm/iocage
{
   "action" : "cleantemplates"
}

WebSocket Request:
-------------------------------
{
   "namespace" : "sysadm",
   "args" : {
      "action" : "cleantemplates"
   },
   "id" : "fooid",
   "name" : "iocage"
}

Response:
-------------------------------
{
  "args": {
    "cleantemplates": {
      "success": "All templates have been cleaned."
    }
  },
  "id": "fooid",
  "name": "response",
  "namespace": "sysadm"
}

src/server/WebBackend.cpp

@@ -708,6 +708,7 @@ RestOutputStruct::ExitCode WebSocket::EvaluateSysadmIocageRequest(const QJsonVal
       else if(act=="listjails"){ retObj = sysadm::Iocage::listJails(); }
       //TEMPLATES
       else if(act=="listtemplates"){ retObj = sysadm::Iocage::listTemplates(); }
+      else if(act=="cleantemplates"){ retObj = sysadm::Iocage::cleanTemplates(); }
       //RELEASES
       else if(act=="listreleases"){ retObj = sysadm::Iocage::listReleases(); }
       else if(act=="fetchreleases"){ retObj = sysadm::Iocage::fetchReleases(in_args.toObject()); }