As a visitor I should be able to use 3rd party accounts during Bandsy account creation

[Dragon1320]

This allows visitors to create a Bandsy account based on a 3rd party account such as Google instead of having to enter an email and password.

Acceptance criteria:

• User can choose to create a Bandsy account using a 3rd party account instead of entering an email and password.
• User can choose the following accounts during sign-up: Google, Facebook, Twitter.
• User information from the 3rd party account should be fetch-able, e.g. their email, name, etc.