e-mails in simcore should be case-insensitives

[elisabettai]

Long Story Short
When adding a collaborator I want to use the email address I normally use to contact him/her

Expected Behavior
Adding the collaborator with email name.SURNAME@domain should work (I am used to send email to this address)

Actual behaviour
If I add a collaborator with email like name.SURNAME@domain, that doesn't work

Steps to reproduce
A user registers with name.surname@domain in the DB.
Trying adding him to an organization using name.SURNAME@domain fails

Additional context
See #807

[pcrespov]

NOTE:

• consider https://mailchimp.com/resources/are-email-addresses-case-sensitive/
• @elisabettai The local-part of a mailbox MUST BE treated as case sensitive according to https://tools.ietf.org/rfc/rfc5321.txt i.e. ' [email protected]' == '[email protected]' but '[email protected]' != '[email protected]'
• BUT our email server does not care about the local-part :-)
• See RFC 5322 but treat it with suspicion, there seems to exist no universally acknowledged test for a valid email!
• For case-insensitive email:

from pydantic import EmailStr, validate_email

class CaseInsensitiveEmailStr(EmailStr):
    @classmethod
    def validate(cls, value: EmailStr) -> EmailStr:
        _, email = validate_email(value)
        return email.lower()