Improve upgrade-settings to cleanup legacy configs in repositories

[hohwille]

As a IDEasy user, I want ide upgrade-settings to cleanup as much of legacy stuff as possible so that I get my project up-to-date and get rid of warnings.

Currently when repositories are loaded from properties and use git.url or git-url instead of git_url this is raising a legacy warning.
The same applies for eclipse=import instead of import=eclipse.

The command ide upgrade-settings should also fix such legacy stuff and repair it automatically.
See PR #820 and also story #954