added support for MSSQL default intances with windows authentication

[lennartfranke]

Removed the "IntegratedSecurity = false" property, so Integrated Secutiy will not be disabled on a new instance when using connection strings like 'Data Source=.;Integrated Security=True'.

Fixed also an issue on non-english windows version where the 'IIS Check' does not work.

[AlenPelin]

Generally IntegratedSecurity = false was added as a workaround for the issue when importing/exporting solutions between systems where on the one side IntegratedSecurity is used and on the other one is not. I cannot accept this pull request without proper testing so lets postpone it a little bit.

[lennartfranke]

I should have split this into two separate pull requests but i saw you already implemented the fix for non-English locales with 1248c5ab4c0caa8907ac6ae5640afd3393ef5c1a.

Regarding the IntegratedSecurity: You are right, importing/exporting could be a problem, I don't had that in mind when creating the pull request. The import pipeline seem to have it's own processor for updating the ConnectionStrings with SIM.Pipelines.Import.UpdateConnectionStrings which also using IntegratedSecurity = false. I am not sure if it would be good when install and import would behave differently.