Change email validation to match maxipago validation

[carvmarc]

If try a email like bar+foo@test.com, the donation system will accept, but the gateway will reject the payment. So we need to change the validation of email field on the donation form to not accept the + on the email.

[henriquekano]

@carvmarc AFAIK, +, along with other special characters, are valid for the email's local part. Therefore, it's totally possible for a donor to have a bar+foo@gmail.com email address being refused to donate, which sucks...

Of course we can't ignore said error, so I propose first contacting the payment gateway to hear what they have to say and, second, having a flow for these cases to contact the donor explaining the context (by email or any other method) so he can try donating using another email.

What do you think?

[carvmarc]

Sure makes sense contact the gateway, however now that I thought about, as this system will be used for others in the future maybe a better aproach is make the email validation confiigurable.