GH-28 Refactor code to add setting fields from an array

[sudhir-yadav]

This PR refactors the current settings to a single array of fields in one setting.

[hbhalodia]

Hi @sudhir-yadav @pradeep910, This is the exact same code that we had earlier just shorten by adding a foreach loop. I think we need to register only 1 settings and fetch other settings by array key. Something similar to below code.

// Define default array
$defaults = array(
   'setting_1' => 'default_value_1',
   'setting_2' => 'default_value_2',
);

// Register the setting
register_setting( 'my_settings_group', 'my_array_setting', array(
   'type' => 'array',
   'default' => $defaults,
) );

// Update code that uses the setting
$options = get_option( 'my_array_setting', $defaults );
$setting_1 = $options['setting_1'];
$setting_2 = $options['setting_2'];

Of course we need to handle for the settings that are saved with standalone options after implementing above. This is my suggestion, and it would best because we need to call just one option and that would be stored in an array we can fetch by array key.

[hbhalodia]

Also settings callback would be same, there would be no change, just option fetch from settings key.