Rename Slave to Host

The role of a slave as a host for Factorio servers is not well reflected
in its name and has caused confusion among users.  Rename slave to host
to better reflect its role as a host of Factorio servers.

plugins/subspace_storage/instance.js

@@ -13,7 +13,7 @@ class InstancePlugin extends libPlugin.BaseInstancePlugin {
 			this.provideItems(output).catch(err => this.unexpectedError(err));
 		});
 		this.instance.server.on("ipc-subspace_storage:orders", (orders) => {
-			if (this.instance.status !== "running" || !this.slave.connected) {
+			if (this.instance.status !== "running" || !this.host.connected) {
 				return;
 			}
 
@@ -25,7 +25,7 @@ class InstancePlugin extends libPlugin.BaseInstancePlugin {
 
 	async onStart() {
 		this.pingId = setInterval(() => {
-			if (!this.slave.connected) {
+			if (!this.host.connected) {
 				return; // Only ping if we are actually connected to the controller.
 			}
 			this.sendRcon(
@@ -50,7 +50,7 @@ class InstancePlugin extends libPlugin.BaseInstancePlugin {
 
 	// provide items --------------------------------------------------------------
 	async provideItems(items) {
-		if (!this.slave.connector.hasSession) {
+		if (!this.host.connector.hasSession) {
 			// For now the items are voided if the controller connection is
 			// down, which is no different from the previous behaviour.
 			if (this.instance.config.get("subspace_storage.log_item_transfers")) {