VAT Number Issues.

[laranz]

• [x] 1. Change the button color to primary, https://user-images.githubusercontent.com/208945/117018343-08960c80-ad12-11eb-8de1-dc1090ea5452.png for now it looks like a disabled button.

• [ ] 2. We need to display an error message when clicking "Validate", whether the entered number is in wrong format, or it is the right number, or a info message when the server of VIES is down. ( if the server is down, we take all number as valid )

• [x] 3. Now the "error" message of invalid VAT number is displaying at the end, make sure to add it after the VAT input.