all: Remove untrusted feature flag (fixes #109) (#7567)

No longer hide the web UI controls for the new untrusted/encrypted
device feature. Testing hasn't been very widespread, but there has been
some and quite a few bugs have been caught and fixed. I believe its time
to not hide it anymore, and cautiously recommend usage. E.g. mention
that the feature hasn't been widely used yet and anyone using it is an
early adopter, but drop the bit about not using it with production data.
We can maybe stress the need for backups in general and especially
using this.

lib/api/api.go

@@ -65,7 +65,6 @@ const (
 	EventSubBufferSize    = 1000
 	defaultEventTimeout   = time.Minute
 	httpsCertLifetimeDays = 820
-	featureFlagUntrusted  = "untrusted"
 )
 
 type service struct {
@@ -105,7 +104,7 @@ func New(id protocol.DeviceID, cfg config.Wrapper, assetDir, tlsDefaultCommonNam
 	return &service{
 		id:      id,
 		cfg:     cfg,
-		statics: newStaticsServer(cfg.GUI().Theme, assetDir, cfg.Options().FeatureFlag(featureFlagUntrusted)),
+		statics: newStaticsServer(cfg.GUI().Theme, assetDir),
 		model:   m,
 		eventSubs: map[events.EventType]events.BufferedSubscription{
 			DefaultEventMask: defaultSub,
@@ -461,10 +460,6 @@ func (s *service) CommitConfiguration(from, to config.Configuration) bool {
 	// No action required when this changes, so mask the fact that it changed at all.
 	from.GUI.Debugging = to.GUI.Debugging
 
-	if untrusted := to.Options.FeatureFlag(featureFlagUntrusted); untrusted != from.Options.FeatureFlag(featureFlagUntrusted) {
-		s.statics.setUntrusted(untrusted)
-	}
-
 	if to.GUI == from.GUI {
 		// No GUI changes, we're done here.
 		return true