Add program public/private to settings

[deanjones-git]

Admin:

Anyone on the Internet when program is public:

Edge cases to check:
page [program/[program name]/mentors] is inaccessible when program isn't public
when you sign into account that isn't part of public program, your tab layout shows Homepage/All Mentors

Potential improvement:
Make a lot of mentor page a component so that we don't have to edit both files

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