Remove button not working on child grid view

[anncatton]

Several issues to fix:

1. the X button on the grid view of a child table is overlapped by the display component, so isn't accessible.
2. the remove function when accessible is broken (fails with Cannot read property 'id' of undefined)
3. the remove button should show on these entities only:

• children of a group: users, applications, permissions (shown as policies)
• children of a user: groups, applications
• children of an application: users, groups
• children of a policy: users, groups
  Right now the remove button shows on all entities whether there is a valid remove function or not. The button should not show if the remove action is not available.

[anncatton]

The grid view is going to be removed in #192