chore: move app proxying code to workspaceapps pkg (#6998)

* chore: move app proxying code to workspaceapps pkg

Moves path-app, subdomain-app and reconnecting PTY proxying to the new
workspaceapps.WorkspaceAppServer struct. This is in preparation for
external workspace proxies.

Updates app logout flow to avoid redirecting to coder-logout.${app_host}
on logout. Instead, all subdomain app tokens owned by the logging-out
user will be deleted every time you logout for simplicity sake.

Tests will remain in their original package, pending being moved to an
apptest package (or similar).

Co-authored-by: Steven Masley <stevenmasley@coder.com>

coderd/database/dbgen/generator.go

@@ -77,12 +77,23 @@ func APIKey(t testing.TB, db database.Store, seed database.APIKey) (key database
 	secret, _ := cryptorand.String(22)
 	hashed := sha256.Sum256([]byte(secret))
 
+	ip := seed.IPAddress
+	if !ip.Valid {
+		ip = pqtype.Inet{
+			IPNet: net.IPNet{
+				IP:   net.IPv4(127, 0, 0, 1),
+				Mask: net.IPv4Mask(255, 255, 255, 255),
+			},
+			Valid: true,
+		}
+	}
+
 	key, err := db.InsertAPIKey(context.Background(), database.InsertAPIKeyParams{
 		ID: takeFirst(seed.ID, id),
 		// 0 defaults to 86400 at the db layer
 		LifetimeSeconds: takeFirst(seed.LifetimeSeconds, 0),
 		HashedSecret:    takeFirstSlice(seed.HashedSecret, hashed[:]),
-		IPAddress:       pqtype.Inet{},
+		IPAddress:       ip,
 		UserID:          takeFirst(seed.UserID, uuid.New()),
 		LastUsed:        takeFirst(seed.LastUsed, database.Now()),
 		ExpiresAt:       takeFirst(seed.ExpiresAt, database.Now().Add(time.Hour)),