API endpoint update

[andy-t-wang]

Changes

• Add new field world_app_button_text that lets dev specify text they want show in the app default is use integration
• added new permission for reviewer role to update verified apps. This is set so we can remove apps from the app store via setting the is_reviewer_app_store_approved flag
• Add localise strings to platform=app
• Updated the return to include featured apps
• Update JSON to now parse the description when returning see spec for new format.
• App and web return types are different
• Add the new button text field to links section
• Reduced world app description length to 35

[igorosip0v]

@andy-t-wang Please, fix the integration test