remove httpPort

we can just use container IP instead of all this httpPort exporting magic.
this is also required for exposing httpPaths feature (we have to otherwise
have multiple httpPorts).

migrations/schema.sql

@@ -65,7 +65,6 @@ CREATE TABLE IF NOT EXISTS apps(
     healthTime TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP, // when the app last responded
     containerId VARCHAR(128),
     manifestJson TEXT,
-    httpPort INTEGER,                        // this is the nginx proxy port and not manifest.httpPort
     accessRestrictionJson TEXT, // { users: [ ], groups: [ ] }
     creationTime TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP, // when the app was installed
     updateTime TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,   // when the last app update was done