browser: Change type Profiles to RuntimeFactory.

This change does the following:
(1) Profiles -> RuntimeFactory
(2) RegisterProfile -> RegisterRuntimeFactory
(3) change remaining package profiles in v.io/x/ref
to runtime/generic.

closes vanadium/issues#470

Change-Id: I4a4957a03b04138bf1108b70ac832ba0ee68b945
MultiPart: 3/3
diff --git a/go/src/v.io/x/browser/runner/main.go b/go/src/v.io/x/browser/runner/main.go
index 95b6cc1..d0c18bf 100644
--- a/go/src/v.io/x/browser/runner/main.go
+++ b/go/src/v.io/x/browser/runner/main.go
@@ -201,7 +201,7 @@
 	lspec.Addrs = rpc.ListenAddrs{{"wsh", ":0"}}
 	// Allow all processes started by this runner to use the proxy.
 	proxyACL := access.AccessList{In: security.DefaultBlessingPatterns(v23.GetPrincipal(ctx))}
-	proxyShutdown, proxyEndpoint, err := profiles.NewProxy(ctx, lspec, proxyACL, "test/proxy")
+	proxyShutdown, proxyEndpoint, err := generic.NewProxy(ctx, lspec, proxyACL, "test/proxy")
 	exitOnError(err, "Failed to start proxy")
 	defer proxyShutdown()
 	vars["PROXY_NAME"] = proxyEndpoint.Name()