Flatten lib namespace

Move all functions and classes currently available through lib/name and
libName to be under a single flat namespace in lib.  This make
reorganising the lib namespace much simpler as the location of symbols
can move without breaking the consumers of lib.

The multi-entrypoint design was already problematic for the web plugin
system which couldn't effectively use it due to how webpack's shared
module system is awkward to set up with multiple entrypoints per package.

plugins/inventory_sync/controller.js

@@ -2,8 +2,7 @@
 const fs = require("fs-extra");
 const path = require("path");
 
-const libFileOps = require("@clusterio/lib/file_ops");
-const libPlugin = require("@clusterio/lib/plugin");
+const lib = require("@clusterio/lib");
 
 const {
 	AcquireRequest,
@@ -34,11 +33,11 @@ async function saveDatabase(controllerConfig, playerDatastore, logger) {
 		let file = path.resolve(controllerConfig.get("controller.database_directory"), "inventories.json");
 		logger.verbose(`writing ${file}`);
 		let content = JSON.stringify(Array.from(playerDatastore));
-		await libFileOps.safeOutputFile(file, content);
+		await lib.safeOutputFile(file, content);
 	}
 }
 
-class ControllerPlugin extends libPlugin.BaseControllerPlugin {
+class ControllerPlugin extends lib.BaseControllerPlugin {
 	async init() {
 		this.acquiredPlayers = new Map();
 		this.playerDatastore = await loadDatabase(this.controller.config, this.logger);