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/disable.js

@@ -0,0 +1,59 @@
+/*
+ * 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')()
+
+const log_levels = [
+    'debug',
+    'info',
+    'notice',
+    'warning'
+]
+
+exports.command = 'disable <command>'
+exports.desc = 'Disable functionality'
+exports.handler = function() {}
+exports.builder = function(yargs) {
+    yargs
+        .command('log-priority <log>', 'Disable log priority [warning|notice|info|debug]', {}, function(argv) {
+            if (log_levels.indexOf(argv.log) != -1) {
+                maxctrl(argv, function(host) {
+                    return updateValue(host, 'maxscale/logs', 'data.attributes.parameters.log_' + argv.log, false)
+                })
+            } else {
+                maxctrl(argv, function() {
+                    error('Invalid log priority: ' + argv.log)
+                    return Promise.reject()
+                })
+            }
+        })
+        .command('maxlog', 'Disable MaxScale logging', {}, function(argv) {
+            maxctrl(argv, function(host) {
+                return updateValue(host, 'maxscale/logs', 'data.attributes.parameters.maxlog', false)
+            })
+        })
+        .command('syslog', 'Disable syslog logging', {}, function(argv) {
+            maxctrl(argv, function(host) {
+                return updateValue(host, 'maxscale/logs', 'data.attributes.parameters.syslog', false)
+            })
+        })
+        .command('account <name>', 'Disable a Linux user account from administrative use', {}, function(argv) {
+            maxctrl(argv, function(host) {
+                return doRequest(host, 'users/unix/' + argv.name, null, { method: 'DELETE'})
+            })
+        })
+        .usage('Usage: disable <command>')
+        .help()
+        .command('*', 'the default command', {}, () => {
+            logger.log('Unknown command. See output of `help disable` for a list of commands.')
+        })
+}