How many invidious instances to run.
See https://docs.invidious.io/improve-public-instance/#2-multiple-invidious-processes for more details on how this is intended to work. All instances beyond the first one have the options channel_threads and feed_threads set to 0 to avoid conflicts with multiple instances refreshing subscriptions. Instances will be configured to bind to consecutive ports starting with services.invidious.port for the first instance.