satellite/console: cache /daily-usage and /usage-report endpoint resp…

…onses for 1 hour

Cache those endpoint responses as they shouldn't change within one hour.

Issue:
storj/storj-private#567

Change-Id: I7baf449dd4a3dd1ecfa28a78b11081c9f3059ec6

satellite/console/consoleweb/consoleapi/usagelimits.go

@@ -180,6 +180,8 @@ func (ul *UsageLimits) UsageReport(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
+	w.Header().Set("Cache-Control", "public, max-age=3600") // Cache the same request for 1 hour.
+
 	wr.Flush()
 }
 
@@ -227,6 +229,8 @@ func (ul *UsageLimits) DailyUsage(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	w.Header().Set("Cache-Control", "public, max-age=3600") // Cache the same request for 1 hour.
+
 	err = json.NewEncoder(w).Encode(dailyUsage)
 	if err != nil {
 		ul.log.Error("error encoding daily project usage", zap.Error(ErrUsageLimitsAPI.Wrap(err)))