Add importprivkeys RPC

In a recent exchange on the Bitcoin Development Mailing List, a noteworthy discussion unfolded around enhancing the functionality and user experience of certain Bitcoin core wallet commands. The conversation highlighted two primary suggestions aimed at refining the system's operational efficiency and simplicity for users.

The first point of discussion revolved around the redundancy and competition between the returns of the 'importprivkeys' and 'importdescriptors' routines. There was a proposition to either merge these returns or allow one to act as a proxy for the other, thereby streamlining the process. This idea underscores the need for a more unified and less confusing approach in handling private keys and descriptors within the Bitcoin core wallet functionalities.

Additionally, the introduction of an 'auto_checksum' boolean flag to the 'importdescriptors' command was suggested. This feature would automate the checksum process for users, simplifying their interaction with the command and potentially reducing errors. While it's unclear whether this suggestion has been previously discussed or considered, the proposal indicates a proactive step towards improving the user interface and experience.

Overall, these discussions reflect an ongoing commitment within the Bitcoin development community to refine and enhance the usability and efficiency of its core wallet commands. By considering such improvements, developers aim to ensure a smoother, more intuitive experience for users interacting with the Bitcoin network.