Update copy in Restricted visibility levels admin settings

What is the problem we are trying to solve?

The copy for the Restricted visibility levels field in the admin area can be confusing.

Proposal to solve this problem

Update the copy to:

• Restrict public: If selected, only logged-in users will be able to see user profiles.
• Restrict internal: If selected, only admin users will be able to create internal projects.
• Restrict private: If selected, only admin users will be able to create projects in private groups.

Designs

Engineering implementation plan

• Add hash with checkbox descriptions to app/helpers/application_settings_helper.rb#L77. Use hash to add help text to each checkbox.
• Update copy in app/views/admin/application_settings/_visibility_and_access.html.haml#L20