devopsmigration init should create configuration.json as utf8-bom

[maf-soft]

I needed some special characters in my config, like in "René". It didn't work with the auto-created file until I saved in VS as UTF8-BOM.

The effect was that VS treated the file correctly as UTF8 and dispayed and saved the characters fine. devopsmigration worked with the file but displayed broken characters and also the filter query returned nothing.

After saving as UTF8-BOM it worked fine. So you could save users some headaches by creating the file directly with the header, so the file format can be detected in all cases.

[MrHinsh]

Please submit a PR with the change.