File Sharing with user

[asabya]

Is your feature request related to a problem? Please describe.
Currently file share api takes an user address as input but does not do anything with it. it just stores the address in the sharing info.

Describe the solution you'd like
There should be two different apis.

• File share api, which shares a file globally
• Some sort of DH encryption over sharing info with the user public key.

[asabya]

#84 is related to this.