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/mocks_test.go

@@ -0,0 +1,46 @@
+// Code generated by MockGen. DO NOT EDIT.
+// Source: github.com/qdm12/gluetun/internal/configuration/settings (interfaces: Warner)
+
+// Package settings is a generated GoMock package.
+package settings
+
+import (
+	reflect "reflect"
+
+	gomock "github.com/golang/mock/gomock"
+)
+
+// MockWarner is a mock of Warner interface.
+type MockWarner struct {
+	ctrl     *gomock.Controller
+	recorder *MockWarnerMockRecorder
+}
+
+// MockWarnerMockRecorder is the mock recorder for MockWarner.
+type MockWarnerMockRecorder struct {
+	mock *MockWarner
+}
+
+// NewMockWarner creates a new mock instance.
+func NewMockWarner(ctrl *gomock.Controller) *MockWarner {
+	mock := &MockWarner{ctrl: ctrl}
+	mock.recorder = &MockWarnerMockRecorder{mock}
+	return mock
+}
+
+// EXPECT returns an object that allows the caller to indicate expected use.
+func (m *MockWarner) EXPECT() *MockWarnerMockRecorder {
+	return m.recorder
+}
+
+// Warn mocks base method.
+func (m *MockWarner) Warn(arg0 string) {
+	m.ctrl.T.Helper()
+	m.ctrl.Call(m, "Warn", arg0)
+}
+
+// Warn indicates an expected call of Warn.
+func (mr *MockWarnerMockRecorder) Warn(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "Warn", reflect.TypeOf((*MockWarner)(nil).Warn), arg0)
+}