[v5.4.0] Offload server components from browser builds of TiddlyWiki (#9183)

* Move Node.js specific files out of the core plugin

* Package server files as new $:/core-server plugin

* Missed commander.js

* Fix crash in browser

* Extend server-only mechanism to be usable by other plugins

* in

* Revert "Extend server-only mechanism to be usable by other plugins"

This reverts commit 3faf503073.

* Revert "in"

This reverts commit b80213128f.

* Reapply "Extend server-only mechanism to be usable by other plugins"

This reverts commit c6c83bc18b.

* Fix test failure

* Move filesystem utilities into core-server

* Move old-style release notes out of the way

* Move the 5.4.0 release note into the right place

* Revert "Move the 5.4.0 release note into the right place"

This reverts commit 3f5c2bfba3.

* Revert "Move old-style release notes out of the way"

This reverts commit ee16e48a43.

core-server/commands/build.js

@@ -0,0 +1,47 @@
+/*\
+title: $:/core/modules/commands/build.js
+type: application/javascript
+module-type: command
+
+Command to build a build target
+
+\*/
+
+"use strict";
+
+exports.info = {
+	name: "build",
+	synchronous: true
+};
+
+var Command = function(params,commander) {
+	this.params = params;
+	this.commander = commander;
+};
+
+Command.prototype.execute = function() {
+	// Get the build targets defined in the wiki
+	var buildTargets = $tw.boot.wikiInfo && $tw.boot.wikiInfo.build;
+	if(!buildTargets) {
+		return "No build targets defined";
+	}
+	// Loop through each of the specified targets
+	var targets;
+	if(this.params.length > 0) {
+		targets = this.params;
+	} else {
+		targets = Object.keys(buildTargets);
+	}
+	for(var targetIndex=0; targetIndex<targets.length; targetIndex++) {
+		var target = targets[targetIndex],
+			commands = buildTargets[target];
+		if(!commands) {
+			return "Build target '" + target + "' not found";
+		}
+		// Add the commands to the queue
+		this.commander.addCommandTokens(commands);
+	}
+	return null;
+};
+
+exports.Command = Command;