Add .mof files syntax support (powershell v4)

[vors]

mof files describes schema of PowerShell DesiredStateConfiguration resources and instances of configurations. It's a pretty hot feature of v4 / v5.

[vors]

.mof files are not essential in v5, but it still will be nice to have them.

[vors]

If anybody would want it, the issues should be created in https://github.com/PowerShell/EditorSyntax
I personally don't care too much about mof at the moment to open an issue about it.