Cancel searching match for the player

[Relrin]

An existing codebase of matchmaking microservice provides a way (at least for now only internally) to delete the player from search queues. All utility code for cancel searching is already written, however it will be great to provide an access via incoming requests to cancel the search.

So, for considering this feature as prepared and ready to use, you will need:

• Append a new endpoint to router with a list of the required permissions
• Write tests with coverage the most common and some corner cases (like an attempt to cancel the search, when the player isn't in a queue)