Registration E-Mail Adress case sensitve

[Thorlogy]

Is your feature request related to a problem? Please describe.

• The registration in the OR Lab via e-mail address would be easier if the e-mail address was case-insensitive.

Describe the solution you'd like

• I would like to be able to enter my email address without having to worry about capitalizing letters. I did not pay attention to this during the registration process.

[bjost2s]

see #130