Support platform-specific execution command in save.properties

What if the developer will need to run SAVE on Windows locally and on Linux in CI/CD? In this case his execution command on different operating systems can differ. So:

1. We need to support following flags. It should be something like in the following examples:

• execCmd.win= ...
• execCmd.linux= ...
• execCmd.mac = ...

2. Flags above should be optional. In case only execCmd flag is set we should override these flags with this value.

This task is very questionable and need investigation and analysis from the developer.