x/ref: Restructure security packages

Here are the renamings:

security               -> lib/security
security/audit         -> lib/security/audit
security/flag          -> lib/security/securityflag
security/serialization -> lib/security/serialization

security/agent                -> services/agent
security/agent/agentd         -> services/agent/agentd
security/agent/keymgr         -> services/agent/keymgr
security/agent/server         -> services/agent/server
security/agent/cache          -> services/agent/internal/cache
security/agent/lru            -> services/agent/internal/lru
security/agent/pingpong       -> services/agent/internal/pingpong
security/agent/test_principal -> services/agent/internal/test_principal

Note that the restructuring is not done, even after this CL is
submitted.  In particular, services/agent is supposed to contain
the *.vdl files, and the client and server libraries are supposed
to live in services/agent/agentlib, per our conventions.  Also
lib/unixfd can also be moved under services/agent/internal.  That
will be fixed in a subsequent CL.

MultiPart: 1/3
Change-Id: Ie9b14083d133a661f0d3a6c33a3ae05e3bac3cd2
diff --git a/profiles/roaming/roaminginit.go b/profiles/roaming/roaminginit.go
index 9edddc6..342422d 100644
--- a/profiles/roaming/roaminginit.go
+++ b/profiles/roaming/roaminginit.go
@@ -21,22 +21,19 @@
 	"v.io/v23/config"
 	"v.io/v23/context"
 	"v.io/v23/rpc"
-	"v.io/x/lib/vlog"
-
 	"v.io/x/lib/netconfig"
 	"v.io/x/lib/netstate"
+	"v.io/x/lib/vlog"
 	"v.io/x/ref/lib/flags"
+	"v.io/x/ref/lib/security/securityflag"
 	"v.io/x/ref/profiles/internal"
 	"v.io/x/ref/profiles/internal/lib/appcycle"
 	"v.io/x/ref/profiles/internal/lib/websocket"
 	_ "v.io/x/ref/profiles/internal/rpc/protocols/tcp"
 	_ "v.io/x/ref/profiles/internal/rpc/protocols/ws"
 	_ "v.io/x/ref/profiles/internal/rpc/protocols/wsh"
-	grt "v.io/x/ref/profiles/internal/rt"
+	"v.io/x/ref/profiles/internal/rt"
 	"v.io/x/ref/services/debug/debuglib"
-
-	// TODO(cnicolaou,ashankar): move this into flags.
-	sflag "v.io/x/ref/security/flag"
 )
 
 const (
@@ -61,7 +58,7 @@
 		Addrs: rpc.ListenAddrs(lf.Addrs),
 		Proxy: lf.ListenProxy,
 	}
-	reservedDispatcher := debuglib.NewDispatcher(vlog.Log.LogDir, sflag.NewAuthorizerOrDie())
+	reservedDispatcher := debuglib.NewDispatcher(vlog.Log.LogDir, securityflag.NewAuthorizerOrDie())
 
 	ac := appcycle.New()
 
@@ -72,7 +69,7 @@
 			listenSpec.AddressChooser = func(string, []rpc.Address) ([]rpc.Address, error) {
 				return []rpc.Address{&netstate.AddrIfc{addr, "nat", nil}}, nil
 			}
-			runtime, ctx, shutdown, err := grt.Init(ctx, ac, nil, &listenSpec, commonFlags.RuntimeFlags(), reservedDispatcher)
+			runtime, ctx, shutdown, err := rt.Init(ctx, ac, nil, &listenSpec, commonFlags.RuntimeFlags(), reservedDispatcher)
 			if err != nil {
 				return nil, nil, shutdown, err
 			}
@@ -115,7 +112,7 @@
 	listenSpec.StreamName = SettingsStreamName
 	listenSpec.AddressChooser = internal.IPAddressChooser
 
-	runtime, ctx, shutdown, err := grt.Init(ctx, ac, nil, &listenSpec, commonFlags.RuntimeFlags(), reservedDispatcher)
+	runtime, ctx, shutdown, err := rt.Init(ctx, ac, nil, &listenSpec, commonFlags.RuntimeFlags(), reservedDispatcher)
 	if err != nil {
 		return nil, nil, shutdown, err
 	}
@@ -133,7 +130,7 @@
 // monitorNetworkSettings will monitor network configuration changes and
 // publish subsequent Settings to reflect any changes detected.
 func monitorNetworkSettingsX(
-	runtime *grt.Runtime,
+	runtime *rt.Runtime,
 	ctx *context.T,
 	watcher netconfig.NetConfigWatcher,
 	prev netstate.AddrList,