- main reason being it's a burden to always define sentinel errors at global scope, wrap them with `%w` instead of using a string directly
- only use sentinel errors when it has to be checked using `errors.Is`
- replace all usage of these sentinel errors in `fmt.Errorf` with direct strings that were in the sentinel error
- exclude the sentinel error definition requirement from .golangci.yml
- update unit tests to use ContainersError instead of ErrorIs so it stays as a "not a change detector test" without requiring a sentinel error
- `PUBLICIP_API` accepts a comma separated list of ip data sources, where the first one is the base default one, and sources after it are backup sources used if we are rate limited.
- `PUBLICIP_API` defaults to `ipinfo,ifconfigco,ip2location,cloudflare` such that it now has `ifconfigco,ip2location,cloudflare` as backup ip data sources.
- `PUBLICIP_API_TOKEN` accepts a comma separated list of ip data source tokens, each corresponding by position to the APIs listed in `PUBLICIP_API`.
- logs ip data source when logging public ip information
- assume a rate limiting error is for 30 days (no persistence)
- ready for future live settings updates
- consider an ip data source no longer banned if the token changes
- keeps track of ban times when updating the list of fetchers