“SQ unveiled a product roadmap in establishing a bitcoin payment ecosystem, leveraging Square hardware expertise with Cash App user experience findings. Products include a BTC Wallet, which will allow users to self-custody BTC through a solution set that encompass a mobile app, cloud service & a hardware component, and a Bitcoin mining initiative, which should help democratize BTC mining by allowing everyday consumers to purchase cloud mining services.” 挖掘机这一块没看懂，cloud mining service对于SQ自产的挖掘机是个啥？$Block(SQ)$