Add sitecore_db attribute to specify the permanent location of *.mdf & *.ldf files.

[tomharrison]

Currently, the sitecore_db resource will only attach the given databases, leaving them in whichever location the user originally saved the files.

The resource should allow the user to specify the final, permanent location in which these files should be stored (such as the default SQL Server directory), and copy them there before attaching.

[jeroendekorte]

I'm preparing a pull request for this together with Active Dir. group support for SQL permissions. Give me a week for this and I hope this will help...

[jeroendekorte]

I opened the PR with this option. Hopefully it will be merged soon ;)