Add a force disconnect option to clean all the resources from the agent plane

[imrajdas]

On the disconnect agent, we are deleting subscriber deployment and agent-config config map currently. As part of force disconnect, we need to delete all the resources which are present here.

Introduce a new request type as "force-disconnect". For ref- https://github.com/litmuschaos/litmus/blob/9837df11cd65e14cc18fb50c11ca367acee2be67/litmus-portal/graphql-server/pkg/cluster/handler/handler.go#L199

[imrajdas]

cc: @hextechpal