Add an option to create accounts compatible with Spark L2 Bitcoin

[bitcoinuser]

Hi,

Many people consider Proton Wallet not to store life savings, but instead to store low Bitcoin amount and I think they are correct. So in my opinion make a lot of sense to implement Lightning, but instead of implementing Lightning directly, Proton should integrate https://spark.info/ L2 Bitcoin that has interoperability with Lightning. Users could choose to create Proton accounts compatible with Spark Bitcoin Layer. I think would be amazing, please consider this. Thanks.