[Ruby] Allow general purpose faraday connection configuration

Created by: jethrodaniel

When used with faraday library, allows configuration to specify blocks that will be used to configure the faraday connection instance directly.

This is needed to support changing the adapter on the connection instance without doing so globally via Faraday.default_adapter=.

Issue: https://github.com/OpenAPITools/openapi-generator/issues/14422

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CC ruby technical committee: @cliffano @zlx @autopp