Long Load times while validation occurs

[bahusafoo]

Currently, validation happens in a single job in the background. This is problematic for large games as it will take a long time to calculate/check hashes of many/large files. The plan is to chunk this up into several background jobs that run in parallels, reducing the overall time it takes to finish validation. The last update to the launcher validation scene provided multi-threading, this enhancement will be the next piece needed to accomplish the behavior ultimately desired here.