Provider controll API is added.

Provider controll API is added.

Provider can select the termination & reactivation behaviours of master.
As default setting, the master will terminate the provider if it has no running instances.
And it will reactivate the provider if a provider has termianted abnormally even though it has running instances.

But using this new API, the provider can select what the master should do for those cases.

To make the disconnection from a provider without termination a provider,
The provider now support the "disconnect" event.
So the master will send "disconnect" request instead of "terminate".

Change-Id: Iec89cc1c762ceadcf96ee1085ef481f61848d835