MM-10417 Add local image proxy and enable by default (#9967)

* MM-10417 Add local image proxy and enable by default

* Remove unused function

* Add dependencies for willnorris/imageproxy

* Fixed compilation errors

* Lock to the master version of willnorris/imageproxy

* Fix atmos/camo proxy when no SiteURL is specified

* Re-add default values for deprecated settings

* Fix unit tests added by merge

* Pass imageproxy to App struct

* Remove unneeded locking when creating the image proxy

* Remove empty test file

app/server.go

@@ -30,6 +30,7 @@ import (
 	"github.com/mattermost/mattermost-server/model"
 	"github.com/mattermost/mattermost-server/plugin"
 	"github.com/mattermost/mattermost-server/services/httpservice"
+	"github.com/mattermost/mattermost-server/services/imageproxy"
 	"github.com/mattermost/mattermost-server/services/timezones"
 	"github.com/mattermost/mattermost-server/store"
 	"github.com/mattermost/mattermost-server/utils"
@@ -110,6 +111,8 @@ type Server struct {
 
 	HTTPService httpservice.HTTPService
 
+	ImageProxy *imageproxy.ImageProxy
+
 	Log *mlog.Logger
 
 	joinCluster        bool
@@ -165,6 +168,8 @@ func NewServer(options ...Option) (*Server, error) {
 
 	s.HTTPService = httpservice.MakeHTTPService(s.FakeApp())
 
+	s.ImageProxy = imageproxy.MakeImageProxy(s, s.HTTPService)
+
 	if utils.T == nil {
 		if err := utils.TranslationsPreInit(); err != nil {
 			return nil, errors.Wrapf(err, "unable to load Mattermost translation files")