IDEA-120753: Modified tool window weight to be configurable in the Intellij registry

Making a new PR since I accidentally closed the other one. Now using the registry to store the UI designer and standard tool window weights. Since these values are floats, I added the necessary functions to handle floats in RegistryValue and Registry (others exist for double, int, string, etc.). By default, they are set to 0.33 as they were hardcoded.