Conflicts:
	actionpack/lib/action_dispatch/routing/redirection.rb

This reverts commit d8596c4b.

Reason: too many mistakes [ci skip]

This reverts commit 25648ce3.

This allows easy upgrading from the old signed Cookie Store <= 3.2
or the deprecated one in 4.0 (the ones that doesn't use key derivation)
to the new one that signs using key derivation

Updated dependency on bundler to ~> 1.2.2

Specifically, remove `ActionDispatch::Head` in favor of `Rack::Head`.

Closes #8232 [ci skip]

Use if..else conditions instead of return guards.
Use _ for not used arguments when iterating.
Set the path variable directly instead of using an empty string and <<.

Introduced in 4a4de567.

regarding linking to Kindle

Use div

Introduce `ActionView::Template::Handlers::ERB.escape_whitelist`

This is a list of mime types where template text is not html escaped
by default. It prevents `Jack & Joe` from rendering as
`Jack & Joe` for the whitelisted mime types. The default whitelist
contains text/plain.

This follows a whitelist approach where plain text templates are
not escaped, and all the others (json, xml) are. The mime type is
assumed to be set by the abstract controller.

Since ActionView::Helpers::ActiveRecordHelper is removed.