Convert cloud related relative paths to absolute paths(if they exist)

The cloud configuration file can point to a relative master file:

```
master_config: another/dir
```

We just convert those into `<cloud-config-dir>/another/dir` if the path
exists.

This also works for `providers_config` and `profiles_config`
Merge pull request #13642 from s0undt3ch/hotfix/cloud-relative-to-absolute-paths

Convert cloud related relative paths to absolute paths(if they exist)