New report router and user reporting refactoring (#25713)

* Added materialized view migration

* Renamed mat view

* Added channel membership mat view and indexes

* Added channel membership mat view and indexes

* Added new index

* WIP

* Simplifying user reporting code

* Created app and API layer for cahnnel reporting, reporting refactoring in general

* New router

* Remobved channel reporting meanwhile

* Upodated autogenerated stuff

* Lint fix

* Fixed typo

* api vet

* i18n fix

* Fixed API vetting and removed channel reporting constants

* yaml

* removed app pagination tests

server/channels/app/report.go

@@ -0,0 +1,32 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package app
+
+import (
+	"net/http"
+
+	"github.com/mattermost/mattermost/server/public/model"
+)
+
+func (a *App) GetUsersForReporting(filter *model.UserReportOptions) ([]*model.UserReport, *model.AppError) {
+	if appErr := filter.IsValid(); appErr != nil {
+		return nil, appErr
+	}
+
+	return a.getUserReport(filter)
+}
+
+func (a *App) getUserReport(filter *model.UserReportOptions) ([]*model.UserReport, *model.AppError) {
+	userReportQuery, err := a.Srv().Store().User().GetUserReport(filter)
+	if err != nil {
+		return nil, model.NewAppError("GetUsersForReporting", "app.report.get_user_report.store_error", nil, "", http.StatusInternalServerError).Wrap(err)
+	}
+
+	userReports := make([]*model.UserReport, len(userReportQuery))
+	for i, user := range userReportQuery {
+		userReports[i] = user.ToReport()
+	}
+
+	return userReports, nil
+}