IdentityUser userToAdd = new IdentityUser()
                {
                    UserName = "bob",
                    NormalizedUserName = "BOB",
                    Email = "test@test.it",
                    NormalizedEmail = "test@test.it",
                    NewPassword = "XYZ",//password will be hashed by service
                    
                };
``
https://github.com/arduosoft/RawCMS/blob/master/Plugins/RawCMS.Plugins.Core/Stores/RawUserStore.cs

The env variables will be:
RAWCMS_INITIAL_USER, RAWCMS_INITIAL_PASSWORD, RAWCMS_INITIAL_EMAIL

Update documentation accordingly

## acceptance criteria
The following test is perfomend
- set values for RAWCMS_INITIAL_USER, RAWCMS_INITIAL_PASSWORD, RAWCMS_INITIAL_EMAIL different than the default one
- delete db
- start rawcms
- you can log in with the credential provided into env variables

- the documentation on deploy is updated