MongoDB Replica set support - needs documentation update

[artiomchi]

This PR (microsoft/aspire#16698) updates the Aspire MongoDB Builder to add support for building a single node replica set. This will allow applications using transactions or change streams to use MongoDB in Aspire.

The documentation should be updated to explain when this should be used, and how to use it.

The usage itself is simple, when adding a mongo database, add the .WithReplicaSet() call to the builder as follows:

var mongo = builder.AddMongoDB("mongo")
    .WithReplicaSet();