Remove the --cluster options from the DataSource

[ianjevans]

With both the old and the new SNI enabled connection strings for Serverless clusters, there's no need to explicitly add --cluster=<routing-id> as an option to AppDataSource.

Old:

    extra: {
        options: "--cluster=<routing-id>",
        application_name: "docs_simplecrud_typeorm"
    },

New:

    extra: {
        application_name: "docs_simplecrud_typeorm"
    },