Support easy navigation from security groups tab and Edit security group instances

[Prathyusha Vanka]

It is difficult to map appropriate security group to instance after instance is created from Edit security groups.
If there is extra button in security groups tab to add to instances after creating new security group, it will be helpful. Similar to Associate button in Floating IPs tab.

[Gary W. Smith (gary-w-smith)]

Unassigning due to inactivity

[Akihiro Motoki (amotoki)]

We now supports security group association per neutron port in addition to instance security group association, so we need some better navigation for security group association. This can be addressed as part of that effort.