This change both speeds up specs (less strings to allocate) and helps catch
cases where methods in Discourse are mutating inputs.
Overall we will be migrating everything to use #frozen_string_literal: true
it will take a while, but this is the first and safest move in this direction
It is not a setting, and only relevant in specs. The new API is:
```
Jobs.run_later! # jobs will be thrown on the queue
Jobs.run_immediately! # jobs will run right away, avoid the queue
```
Do not send an activation email to users invited via email. They
already confirmed their email address by clicking the invite link.
Users invited via link will need to confirm their email address before
they can login.
This updates tests to use latest rails 5 practice
and updates ALL dependencies that could be updated
Performance testing shows that performance has not regressed
if anything it is marginally faster now.