feat: Added support for virtual host style

[abyss-w]

Add the enable_virtual_style field to the config file, example:

access_key_id: 'ACCESS_KEY_ID_EXAMPLE'
secret_access_key: 'SECRET_ACCESS_KEY_EXAMPLE'
zone: 'zone_name'
host: 'qingstor.com'
port: 443
protocol: 'https'

enable_virtual_style: true

• When enable_virtual_style is set to true, requests will be sent using the virtual host style, e.g. http://BUCKET.<zone_name>.qingstor.com/KEY
• If enable_virtual_style is set to false or not set, requests will be sent using path host style, e.g. http://<zone_name>.qingstor.com/BUCKET/KEY