Refactor and improvements on command

Check available helpers
Default permission: view only
Moved validate setting from helper to command
Turn more easy create a importer
Docblock and improvements on interface
lcfirst on system property
Helper moved to ImporHelper folder
Moved fixtures to ImportHelper
Rename settings to config
Big refactor to move import methods to service

Signed-off-by: Vitor Mattos <vitor@php.rio>

tests/unit/Command/BoardImportTest.php

@@ -23,7 +23,7 @@
 
 namespace OCA\Deck\Command;
 
-use OCA\Deck\Command\Helper\TrelloHelper;
+use OCA\Deck\Command\ImportHelper\TrelloHelper;
 use Symfony\Component\Console\Helper\HelperSet;
 use Symfony\Component\Console\Helper\QuestionHelper;
 use Symfony\Component\Console\Input\InputInterface;
@@ -55,12 +55,12 @@ class BoardImportTest extends \Test\TestCase {
 		$input->method('getOption')
 			->withConsecutive(
 				[$this->equalTo('system')],
-				[$this->equalTo('setting')],
+				[$this->equalTo('config')],
 				[$this->equalTo('data')]
 			)
 			->will($this->returnValueMap([
 				['system', 'trello'],
-				['setting', __DIR__ . '/fixtures/setting-trello.json'],
+				['config', __DIR__ . '/fixtures/config-trello.json'],
 				['data', __DIR__ . '/fixtures/data-trello.json']
 			]));
 		$output = $this->createMock(OutputInterface::class);