Remove logo_change_allowed parameter

All marketplace admins should be able to edit the logo of their
marketplace.
Rebase to master
Merge branch 'logo-change-allowed' of https://github.com/sharetribe/sharetribe into logo-change-allowed
Removed defaults

Removed category_change_allowed, custom_fields_allowed,
terms_change_allowed and privacy_policy_change_allowed.
Feedback_to_admin defaults to true.
Remove mention of privacy_policy_change_allowed
Removed "editing_allowed", fixed remaining tests
Merge pull request #683 from sharetribe/logo-change-allowed

Remove unnecessary community defaults