feat(publicip): resilient public ip fetcher (#2518)

- `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

internal/configuration/settings/helpers_test.go

@@ -1,3 +1,30 @@
 package settings
 
-func boolPtr(b bool) *bool { return &b }
+import gomock "github.com/golang/mock/gomock"
+
+type sourceKeyValue struct {
+	key   string
+	value string
+}
+
+func newMockSource(ctrl *gomock.Controller, keyValues []sourceKeyValue) *MockSource {
+	source := NewMockSource(ctrl)
+	var previousCall *gomock.Call
+	for _, keyValue := range keyValues {
+		transformedKey := keyValue.key
+		keyTransformCall := source.EXPECT().KeyTransform(keyValue.key).Return(transformedKey)
+		if previousCall != nil {
+			keyTransformCall.After(previousCall)
+		}
+		isSet := keyValue.value != ""
+		previousCall = source.EXPECT().Get(transformedKey).
+			Return(keyValue.value, isSet).After(keyTransformCall)
+		if isSet {
+			previousCall = source.EXPECT().KeyTransform(keyValue.key).
+				Return(transformedKey).After(previousCall)
+			previousCall = source.EXPECT().String().
+				Return("mock source").After(previousCall)
+		}
+	}
+	return source
+}