Is your feature request related to a problem? Please describe.

When checking out e.g. the branch of a pull request, I need to first fa (fetch all) and then bl to find the remote branch among the selection options. If Neogit fetched remotes automatically at an interval, this would not be necessary.

Describe the solution you'd like

I'd like Neogit to automatically fetch from all (or configured) remotes when Neovim starts, or when Neogit starts, at an interval.

See how e.g. Tower does this.

Configuration suggestion:

auto_fetch_remotes_interval_seconds = int | nil -- Nil is default, nil disables

Describe alternatives you've considered

Use a ZSH plug-in such as this one but it seems to requires Oh-my-ZSH which I don't want to use.