This is a fix for the Hashed Storage migration and Rollback procedure
to ignore any project-level validation error that can happen in a
long-running instance.
There are many situations where defaults and acceptable values changed
but, because we didn't provide a migration to "valid" attributes, it
can happen that project will not be `valid? => true`.
Because the changes we are making are limited to setting a project as
read_only or changing the storage_level, it's safe to bypass validation.
Rollback is done similar to Migration for the Hashed Storage.
It also shares the same ExclusiveLease key to prevent both happening
at the same time.
All Hashed Storage related workers now share the same queue namespace
which allows for assigning dedicated workers easily.
We are adding sidekiq workers and service classes to allow to rollback
a hashed storage migration. There are some refactoring involved as well
as part of the code can be reused by both the migration and the rollback
logic.