Summary

The PR #2350 closed the issue #2172 , but additional improvements that were delayed need to be made for the remote list functionality.

Needed improvements

an additional command is needed in the remotelist popup, to fetch the currently selected remote
- this should reuse the fetch popup
the remotelist popup shall be able to display changes to the git remotes that had been done outside of the gitui tui app
- for example: the user added a remote using the standard cli -> the remote should appear in the remotelist popup of the gitui tui automatically
the delete/create/edit functionality inside the app does not need to be globally available and therefore can be renamed to start_remote_[OPERATION_NAME]_flow and moved inside the remotelist popup
the URL that is entered when adding/editing a remote should be validated