refs #11040
In case of falsy `sendWelcomeEmail` config, the blog setup crashed as the setup method implicitly returned undefined instead of promise. This handles the fasly config correctly.
- Adds regression test for pro config blog setup
refs #10060
- Modules extractions done here are meant to make upcoming migration of authentication controller to v2 more manageable and reduce code repetition
- There were couple modules extracted for different areas that controller touches: passwordrest, accept (for invitation), setup
- The aim was to keep changes to the minimum while making small readability improvements to new functions through async/await syntax
- The biggest barrier to make more encapsulated functions was the fact that we mutate options parameter on multiple levels in the controller. e.g mutations of options.data during validation on the password reset ties it up to the implementation of doReset function
