Create a backend route to create admin users by setting the role in firebase as "admin" (ask Adhithya on how roles currently work)

[AmanKAggarwal]

To create admin users, we don't need to provide any UI but we do need a very simple route which just takes in an email and password and registers the user with firebase and sets the role for the user on firebase as "admin"

Request

POST admin
{
    email: <email>,
    password: <password>,
}

Response

Admin created with ID "blah"