Queue improvements

[krystian-panek-vmltech]

now the same queue is used to do 'canRun' and do 'doRun'
however it make block some scripts unintentionally because e.g. when executing in console some script, then for a little moment enabled scripts will be in queue and they will be in 'queued' state telling the console that it cannot be run because queue is false-positively not idle

possible resolutions:

• not use queue to check 'canRun' in ScriptScheduler; just do it sequentially and sync, and then only do 'doRun' async
• introduce separate queue only for 'canRun' and existing queue only used for 'doRun'