Handle landing zones of users with sufficient role removed from project

[mikkonie]

It seems we have not fully considered some scenarios regarding landing zone management, where a user's roles are removed from a project. No one has reported this to me either.

Let's say a user creates a landing zone. Afterwards, the user's role in the project is removed or changed into project guest. This generates the following situation:

• The landing zone still exists in iRODS
• The user can access the landing zone and read/write files
• The user lacks access to operations for validating, moving or deleting the landing zone
• The project owner/delegate can see the zone and apply operations to it

This is confusing and should be clarified. My initial thoughts would be to append the procedure for changing/removing user roles as follows:

• If a landing zone has no files, simply delete it
• Else leave it and remove user read/write access to it, so that owner/delegate can handle cleanup
  • (OR, warn user removing the access and refuse changing of the perms (this is more complicated))
• In the UI, denote that the user is no longer in the project or lacks sufficient permissions

I'm open for comments. Would the above be the best course of action, or should this be handled differently?

Once a plan is agreed upon, I can think of which modify API hooks the implementation needs to go, etc.

This is related to the following issues: #57, #1934, #1935.