Add Convert-LineEnding command

[rkeithhill]

This would be like dos2unix and unix2dos. Running gci *.cpp | Convert-LineEnding with no "switch" parameter should convert line endings to match the current platform. I would expect -Windows and -Unix (or -Linux) mutually exclusive switches to force a specific line-ending independent of the current platform. Not sure if it would be worth adding -macOS switch (for \r line endings) since I "think" that is old, old macs and probably not relevant anymore.

[BarabasGitHub]

Can I nudge this issue? I just searched half the web for a decent solution and they're all kinda bad in their own way. Having something for this OOTB would be great.