MXS-1300: Un-modularize the core

Making the core a module proved to bring more problems than it solved. For
the sake of simplicity in installation and code coverage reporting, the
core is now completely contained in the `lib/` directory.

Also added preliminary coverage reporting with nyc.

maxctrl/lib/link.js

@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2016 MariaDB Corporation Ab
+ *
+ * Use of this software is governed by the Business Source License included
+ * in the LICENSE.TXT file and at www.mariadb.com/bsl11.
+ *
+ * Change Date: 2020-01-01
+ *
+ * On the date above, in accordance with the Business Source License, use
+ * of this software will be governed by version 2 or later of the General
+ * Public License.
+ */
+require('./common.js')()
+
+function addServer(argv, path, targets) {
+    maxctrl(argv, function(host){
+        return doRequest(host, path, function(res) {
+            var servers =_.get(res, 'data.relationships.servers.data', [])
+
+            targets.forEach(function(i){
+                servers.push({id: i, type: 'servers'})
+            })
+
+            // Update relationships and remove unnecessary parts
+            _.set(res, 'data.relationships.servers.data', servers)
+            delete res.data.attributes
+
+            return doAsyncRequest(host, path, null, {method: 'PATCH', body: res})
+        })
+    })
+}
+
+exports.command = 'link <command>'
+exports.desc = 'Link objects'
+exports.handler = function() {}
+exports.builder = function(yargs) {
+    yargs
+        .command('service <name> <server...>', 'Link servers to a service', {}, function(argv) {
+            addServer(argv, 'services/' + argv.name, argv.server)
+        })
+        .command('monitor <name> <server...>', 'Link servers to a monitor', {}, function(argv) {
+            addServer(argv, 'monitors/' + argv.name, argv.server)
+        })
+        .usage('Usage: link <command>')
+        .help()
+        .command('*', 'the default command', {}, () => {
+            logger.log('Unknown command. See output of `help link` for a list of commands.')
+        })
+}