cmcmd: report system errors on more filesystem operations

Print the system error message in case of failure when calling
`CopyFileAlways`, `CopyFileIfDifferent`, `CopyFileIfNewer`,
`CopyADirectory` and `MakeDirectory`.

Remove unnecessary `cmSystemTools` wrappers for `CopyFileIfNewer` and
`CopyADirectory`.

Fixes: #18276
8 files changed