[Feature]: Improve version mismatch reporting

[jaj22]

Currently players seem to find it very easy to ignore the version mismatch hint, and for an easily-ignored message the behaviour (quit initClient) is not good. Maybe better to pop up a dialog with two options: Abort mission and continue at own risk. Abort could be defaulted so it simply dumps you back to role selector, although that's potentially dangerous because the dialog might be closed by mods.