Find all the available instances for a particular application.

The InteropBroker.fdc3HandleFindInstances must be overriden to return the relevant array of AppIdentifiers.

Example

const appInstances = await fdc3.findInstances({ appId: 'openfin-app' });

//This returns an array of AppIdentifiers:
//[
//    { appId: 'openfin-app', instanceId: '41938512-d5c1-416a-9c2c-8a6874244fe31' },
//    { appId: 'openfin-app', instanceId: 'b94f6c11-8fed-4a53-8106-7725a908b4bc' }
//]