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/core.js

@@ -0,0 +1,97 @@
+/*
+ * 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.
+ */
+
+var fs = require('fs')
+var program = require('yargs');
+
+const maxctrl_version = '1.0.0';
+
+program
+    .version(maxctrl_version)
+    .group(['u', 'p', 'h', 's', 't', 'q', 'tsv'], 'Global Options:')
+    .option('u', {
+        alias:'user',
+        global: true,
+        default: 'admin',
+        describe: 'Username to use',
+        type: 'string'
+    })
+    .option('p', {
+        alias: 'password',
+        describe: 'Password for the user',
+        default: 'mariadb',
+        type: 'string'
+    })
+    .option('h', {
+        alias: 'hosts',
+        describe: 'List of MaxScale hosts. The hosts must be in ' +
+            'HOST:PORT format and each value must be separated by spaces.',
+        default: 'localhost:8989',
+        type: 'array'
+    })
+    .option('s', {
+        alias: 'secure',
+        describe: 'Enable HTTPS requests',
+        default: 'false',
+        type: 'boolean'
+    })
+    .option('t', {
+        alias: 'timeout',
+        describe: 'Request timeout in milliseconds',
+        default: '10000',
+        type: 'number'
+    })
+    .option('q', {
+        alias: 'quiet',
+        describe: 'Silence all output',
+        default: 'false',
+        type: 'boolean'
+    })
+    .option('tsv', {
+        describe: 'Print tab separated output',
+        default: 'false',
+        type: 'boolean'
+    })
+
+    .command(require('./list.js'))
+    .command(require('./show.js'))
+    .command(require('./set.js'))
+    .command(require('./clear.js'))
+    .command(require('./enable.js'))
+    .command(require('./disable.js'))
+    .command(require('./create.js'))
+    .command(require('./destroy.js'))
+    .command(require('./link.js'))
+    .command(require('./unlink.js'))
+    .command(require('./start.js'))
+    .command(require('./stop.js'))
+    .command(require('./alter.js'))
+    .command(require('./rotate.js'))
+    .command(require('./call.js'))
+    .help()
+    .demandCommand(1, 'At least one command is required')
+    .command('*', 'the default command', {}, () => {
+        console.log('Unknown command. See output of `help` for a list of commands.')
+    })
+
+module.exports.execute = function(argv, opts) {
+    if (opts && opts.extra_args) {
+        // Add extra options to the end of the argument list
+        argv = argv.concat(opts.extra_args)
+    }
+
+    return new Promise(function(resolve, reject) {
+        program
+            .parse(argv, {resolve: resolve, reject: reject})
+    })
+}