Allow the authentication texts to be customizeable

[hannesortmeier]

Hey there,

thank you for writing this fine piece of software!

I would love to be able display different texts on the auth ui components like the sign up component. For example, instead of E-mail, I would like to display E-Mail and instead of Create a new account, I would like to display something in german.

This could help with adapting wasp in non-englisch speaking countries.

I think this is heavily out-of-scope but I was even thinking about integrating multi language support. This could be a great feature!

Thanks!

[infomiho]

Related to #2061 and #1104