To be GDPR compliant we need to provide privacy statement. These should
be linked on the index page. So as soon as a document exist under
`public/docs/privacy.md` the link will show up.

Since we already add legal links, we also add Terms of Use, which will
show up as soon as `public/docs/terms-of-use.md` exists.

This should allow everyone to provide the legal documents they need for
GDPR and other privacy and business laws.

Signed-off-by: Sheogorath <sheogorath@shivering-isles.com>