[BUG] Exception on first time startup

[shurwit]

Describe the bug
Currently if you run the latest version of this Building Block for the first time you will get the following exception:

notifications/core.queueLogic.lockQueue.func1({0x7fe60af28698?, 0xc000095a40})
	/notifications-app/core/app_queue.go:167 +0x152
notifications/driven/storage.(*Adapter).PerformTransaction.func1({0x13471a8, 0xc000095a40})
	/notifications-app/driven/storage/adapter.go:66 +0x6e
go.mongodb.org/mongo-driver/mongo.(*Client).UseSessionWithOptions(0x1342550?, {0x1342588, 0xc001075e00}, 0xc00003aea0?, 0xc0000ef598)
	/notifications-app/vendor/go.mongodb.org/mongo-driver/mongo/client.go:768 +0x19c
go.mongodb.org/mongo-driver/mongo.(*Client).UseSession(...)
	/notifications-app/vendor/go.mongodb.org/mongo-driver/mongo/client.go:754
notifications/driven/storage.(*Adapter).PerformTransaction(0xc0000a0058?, 0xc001075da0?, 0x0?)
	/notifications-app/driven/storage/adapter.go:59 +0xe5
notifications/core.queueLogic.lockQueue({0xc0000a41c0, {0x134cb08, 0xc0000a0058}, {0x1343900, 0xc0004a81e0}, 0x0, 0xc00106cea0})
	/notifications-app/core/app_queue.go:184 +0x162
notifications/core.queueLogic.processQueue({0xc0000a41c0, {0x134cb08, 0xc0000a0058}, {0x1343900, 0xc0004a81e0}, 0x0, 0xc00106cea0})
	/notifications-app/core/app_queue.go:53 +0x105
notifications/core.queueLogic.start({0xc0000a41c0, {0x134cb08, 0xc0000a0058}, {0x1343900, 0xc0004a81e0}, 0x0, 0xc00106cea0})
	/notifications-app/core/app_queue.go:40 +0xc6
notifications/core.(*Application).Start(0xc000619b00)
	/notifications-app/core/app.go:68 +0xd0
main.main()
	/notifications-app/main.go:146 +0x1305

To Reproduce
Steps to reproduce the behavior:

1. Run new instance of Notifications BB
2. See crash on startup

Expected behavior
This is caused by a nil dereference of the message queue since no queue exists. We need to either handle this nil case appropriately or perform the necessary first time setup when the BB starts to ensure that no manual database configuration is necessary.