Default config is invalid

Problem/Motivation

When installing the module, it generates this config:

_core:
  default_config_hash: s98wd6S6PgBYBZ-NcxuBx30TeWOXFnVzTJC6Ntx33HY
email_login_otp:
  allow_enable_disable: 1
  redirect: 0
  message_type: status
  redirect_message: 'Please setup 2FA via email.'
  resend_wait_time: 2
allow_enable_disable: 1
redirect: 0
message_type: status
redirect_message: 'Please setup 2FA via email.

I think it's because config/install/email_login_otp.config.yml has the config under a email_login_otp: but the module expects it at the root.

A side effect of this is that by default resend_wait_time is not set.
I see that email_login_otp_install() converts the config but does not handle resend_wait_time.

Steps to reproduce

drush en email_login_otp
drush cget email_login_otp.config

Proposed resolution

I think the default config YAML should look like this:

allow_enable_disable: 1
redirect: 0
message_type: 'status'
redirect_message: 'Please setup 2FA via email.'
resend_wait_time: 2

And email_login_otp_install() could be removed.

Remaining tasks

User interface changes

API changes

Data model changes