Fixes #19588 - Allow setting custom headers in CSV export

Fixes #19930: Skip adding permissions to default_roles during migrate

Fixes #19582 - Alert when puppetclass is not saved due to error

Fixes #19418 - Correctly route cancel button on host form

Fixes #19631 - ComputeResource with KeyPair can be removed

The concern for removing the compute resources with keypairs was trying
to destroy the compute resource too early. Also, this deletion already
happened because of the has_one :dependency => :destroy relation...

Fixes #19762 - upgrade to rubocop 0.49.1

Fixes #19585 - Allow csv export of nested attributes

This is required for example to export host facet attributes.

Fixes #19646 - improve inline help

Fixes #15861 - increase size of audited_changes column

In mysql text type is limited to 64K, while in psql
there's no limit. Changeing type to MEDIUMTEXT,
which limited to 16MB, should solve this issue in mysql

Fixes #19700 - update rubocop rules

The following changes have been made:

- Performance/RedundantMerge:
changes lines such as:
```not_found_message.merge! :message => options```
to:
```not_found_message[:message] = options```

- converts str.match() to str =~ ()...