Allow students under age 13 to view applab and gamelab projects

[davidsbailey]

Description

Allow signed-in users under age 13 who do not have a teacher who has agreed to our terms of service agreement to view applab and gamelab projects which do not store data. Also add a few protections against these users creating any applab or gamelab app, or from accessing apps which use data. Also see project work item list doc.

Terminology

in all cases below, students who are under 13 are treated as over 13 if they have a teacher who has accepted the terms of service. A signed-in user who is under 13 and has no teacher (or the teacher has not accepted the terms of service) is "too young". This nomenclature is not great and I'm open to changing it. Alternatives:

• recompute isSignedIn && !is13Plus && !hasAcceptedTerms in many places and assign them to individual names like canStoreData, canRemix, etc.

• rename isTooYoung to isYoungWithoutTeacher or something more descriptive.

isTooYoung must remain distinct from is13Plus, because some parts of the product will depend strictly on the user's actual age regardless of whether they have a teacher.

Routing changes

• signed-in users under 13 can access view and share links for applab projects which do not store data
• signed-in users under 13 cannot access view and share links for applab projects which do store data (allowed by dashboard, redirected by the client)

Visible changes

A few buttons have been hidden for actions which are not allowed for young students.

before

after

There are also a couple of existing warning messages that weren't showing before and are now showing:

too young, with teacher, terms not accepted

too young, without teacher

[Bjvanminnen]

lgtm