Loki: Introduce new limited_log_push_errors. (#9568)

**What this PR does / why we need it**:
Introduce a new configuration named `limited_log_push_errors` that will
be implemented.
The configuration is being introduced on a separated PR to facilitate
future rollbacks.

**Which issue(s) this PR fixes**:
N/A

pkg/runtime/config.go

@@ -4,6 +4,10 @@ type Config struct {
 	LogStreamCreation     bool `yaml:"log_stream_creation"`
 	LogPushRequest        bool `yaml:"log_push_request"`
 	LogPushRequestStreams bool `yaml:"log_push_request_streams"`
+
+	// LimitedLogPushErrors is to be implemented and will allow logging push failures at a controlled pace.
+	// TODO(dylanguedes): implement it.
+	LimitedLogPushErrors bool `yaml:"limited_log_push_errors"`
 }
 
 // TenantConfig is a function that returns configs for given tenant, or
@@ -54,3 +58,7 @@ func (o *TenantConfigs) LogPushRequest(userID string) bool {
 func (o *TenantConfigs) LogPushRequestStreams(userID string) bool {
 	return o.getOverridesForUser(userID).LogPushRequestStreams
 }
+
+func (o *TenantConfigs) LimitedLogPushErrors(userID string) bool {
+	return o.getOverridesForUser(userID).LimitedLogPushErrors
+}