Wallet modal - Consistent style

[RominaMarchetti]

In order to keep consistency between the Client's and dApps' wallet modal let's do the following:

• The title should be Sign In or Create an Account.
• The subtitle should be Choose a method to connect.
• All the buttons will be wide rectangles instead of squares.
• Try to keep all the corners (containers, buttons) more rounded.
• Adjust the close button style.
• All the text should be aligned in the center.
• Exceptions for the Client: add Enter as Guest button and use the light theme instead the dark one used for dApps.
• After clicking Fortmatic wallet, hide the wallet modal behind (it's weird to overlap modals). If the player closes by any chance the Fortmatic modal, then show the wallet selection again.

Visual examples of how the modal should look