ngit-cli : feat(login): store in git config and use cache

replace ngit yaml file config with:

* nsec / ncryptsec / npub in git config in nostr.* namespace

* sql database cache for metadata and relay events

allow different logins to be used for different git repositories by

storing login in local git config

https://github.com/DanConwayDev/ngit-cli/commit/173ab188b326fbe78cfba4ab455a74619f4556bb