Add config.php in root on install

[nabeelio]

Add it to get parsed and override any configs, vs adding them all manually in several places in the env.php file. Mainly for forward compatibility and easier to upgrade, don't need to touch any of the files in the config/ folder. E.g:

return [
  # overrides the app.php config file
  'app' => [
    'name' => 'phpVMS Airlines',
  ],
];

tasks

• See ServiceProvider::mergeConfigFrom
• See \Illuminate\Support\Arr
• create stub in installer
  • move database/mail settings
• move phpvms settings
• read and parse in AppServiceProvider (replace the local.config.php entry)
• docs

Sample file: https://gist.github.com/nabeelio/a93b062121a29647efe43b3508ccffe8