"Request data" for closed resources

[stranak]

Closed (restricted) resources, i.e. those, that can't be directly downloaded, should include a button "Request data" that will simply send an email to the submitter, requesting a copy of the data.

This is the simplest solution possible.

• The email should be created by a web form on the server, not revealing the submitter email address. (I know it is not exactly protected anyway)
• The form would have a field for reason/use case and contact info.

[stranak]

Later we can have a proper solution for signing licenses, etc. But this is very simple, it can work immediately and solve the problem of closed resources for many users.