Add control of required fields when using setters in CliApplication.php

[elcreator]

Use

        $this->addCommandClass(\App\Command\Something::class, 'run', [self::OPT_REQUIRED => ['id', 'name']]);

if only some fields are required or

        $this->addCommandClass(\App\Command\Something::class, 'run', [self::OPT_REQUIRED_ALL => true]);

if all of them are required for given command.

Defaults are [] and false to ensure compatibility with current version.

[elcreator]

fixes https://github.com/vanilla/garden-cli/issues/47

[elcreator]

@tburry