v3.6.0-rc1 Lasagne

Special thanks to @cillian, @drummer83 and @luisramos0! 💐

This release candidate contains the upgrade to Rails 5.0 and plenty more technical upgrades.

User facing changes 👀

• #7158 Update translations
• #7062 Instance managers can now switch to requiring shoppers to accept the platform's terms of service on every checkout.
• #6980 Cleaner and consistent design of front-end footer
• #7015 Fixed a bug where non-producing enterprises would show up on the shopfront's list of producers.
• #7014 Fixed a bug where orders in the Resumed state could not access the payments tab.
• #6879 Use new order balance calculation in bulk coop report but hidden under a feature toggle.

Technical changes 🔧

• #7121 Data migration to fix any adjustments missing an order id
• #7045 Add automated testing for unit price in the shopfront
• #7142 Tiny improvement of specs using OutstandingBalance class
• #7148 Bump cancancan to 1.15.0
• #7143 Reduce retention period of Spree state changes and log entries from 6 to 3 months
• #7095 Adapt controllers code to rails 5.2
• #7096 Adapt code to rails 5.2
• #7116 Better test InvoiceRenderer. This entails a tiny refactoring
• #7149 Rearrange order updater tests to make them method-centric
• #7140 Rearrange and cover the balance in subs mailer specs
• #6973 Line Item tax amounts are displayed correctly when using included taxes.
• #7146 Updated some deprecated syntax: configs, callbacks, associations, alias_method_chain
• #7111 Replace assets test config with public_file_server
• #7082 Bump i18n from 1.8.5 to 1.8.9
• #7023 Improved efficiency when revoking adjustment eligibility.
• #7024 Removed unnecessary code Spree::Config[:auto_capture]
• #7145 Temporarily skip embedded shopfront flaky spec
• #7122 Updated translations
• #7067 Bump rspec-rails from 4.0.2 to 4.1.2
• #7136 Rearrange and extend some OrderMailer unit-tests
• #7107 A context block was added to the existing spec file line_items_controller.spec. This adds a payment to an order (payment_state = paid) and destroys a line item, changing the payment state to credit_owed.
• #7137 Fix failing timezone-related specs
• #7037 Bump awesome_print from 1.8.0 to 1.9.2
• #7084 Bump acts-as-taggable-on from 4.0.0 to 7.0.0
• #7104 Bump compass-rails from 2.0.1 to 4.0.0
• #7085 Bump responders from 2.4.1 to 3.0.1
• #7110 Fixed displaying of errors when payment capture fails.
• #7133 Fix env deprecated in Rails 5.0
• #7135 Updated paypal_items_builder_spec test setup
• #7134 Feature-test payments report
• #7132 Replaced deprecated reload syntax
• #7128 Use timezone as hour and minute offset from UTC in terms_and_conditions_spec.rb
• #7042 Fix most money gem deprecation warnings.
• #7113 Fix deprecation warning related to #reload
• #6938 Increased test coverage on Paypal adjustments handling
• #7125 Run Github CI build on pull_request event
• #7019 Bump monetize from 1.10.0 to 1.11.0
• #7114 Move invoice-related specs to their own file