Start using USCS asset ids instead of autogenerated IDS

[wzin]

Overview:

This ticket has a lot of context for this issue https://github.com/EndPointCorp/ros_cms/issues/643 - please read it first.

The general problem we're having is that Smooth Transitions (what I imagine will be used once LG ditches binary earth completely) is the assets persistence. Provided that we want identical assets to persist between USCS messages, we make a predictable, reproducible but unique ID out of it (based in asset's attributes) when USCS message comes and we compare it with existing assets loaded on the screens. The problem is that it's done on the fly by a part of the system that does know listen to USCS messages (readiness node namely) but to adhocbrowsers' topics. Because it listens to adhocbrowsers, it does not know how many adhocbrowsers are there and how many adhocbrowsers should report their readiness. It of course does it's best effort but it's innacurate.

It's a design flaw.

The way it should be done is that readiness node should listen to USCS messages and get the list of IDS of browsers that should "join" the scene. The information should be coming directly from the USCS, not from the adhoc browser director bridge: https://github.com/EndPointCorp/lg_ros_nodes/blob/2dfff1855cd6f737111e8e852c8ee33b8b014e58/lg_common/src/lg_common/adhoc_browser_director_bridge.py.

Currently readiness node listens on USCS messages to see how many browsers should join but it does not know about their IDs. It prevents readiness now from resigning from waiting on browsers tht already exist (e.g. identical assets across the scenes).

Requirements:

• [ ] make readiness node extract IDs of assets that it should wait for
• [ ] make readiness node compare existing assets with incoming assets to provide persistence

Testing scenario

• test smooth transitions thoroughly:
  • create a scene with several adhoc browsers - all of them should have the smooth transition checkbox checked
  • create another scene with smooth transitions
  • switch between those scenes and scenes without smooth transitions
  • set the scene with smooth transitions as the initial scene and relaunch