Auth: Add anonymous users view and stats (#78685)

* Add anonymous stats and user table

- anonymous users users page
- add feature toggle `anonymousAccess`
- remove check for enterprise for `Device-Id` header in request
- add anonusers/device count to stats

* promise all, review comments

* make use of promise all settled

* refactoring: devices instead of users

* review comments, moved countdevices to httpserver

* fakeAnonService for tests and generate openapi spec

* do not commit openapi3 and api-merged

* add openapi

* Apply suggestions from code review

Co-authored-by: Alex Khomenko <Clarity-89@users.noreply.github.com>

* formatin

* precise anon devices to avoid confusion

---------

Co-authored-by: Alex Khomenko <Clarity-89@users.noreply.github.com>
Co-authored-by: jguer <me@jguer.space>

pkg/api/admin.go

@@ -3,6 +3,7 @@ package api
 import (
 	"context"
 	"net/http"
+	"time"
 
 	"github.com/grafana/grafana/pkg/api/response"
 	ac "github.com/grafana/grafana/pkg/services/accesscontrol"
@@ -63,6 +64,12 @@ func (hs *HTTPServer) AdminGetStats(c *contextmodel.ReqContext) response.Respons
 	if err != nil {
 		return response.Error(500, "Failed to get admin stats from database", err)
 	}
+	thirtyDays := 30 * 24 * time.Hour
+	devicesCount, err := hs.anonService.CountDevices(c.Req.Context(), time.Now().Add(-thirtyDays), time.Now().Add(time.Minute))
+	if err != nil {
+		return response.Error(500, "Failed to get anon stats from database", err)
+	}
+	adminStats.AnonymousStats.ActiveDevices = devicesCount
 
 	return response.JSON(http.StatusOK, adminStats)
 }