Support a file tree view in :Neogit

[SamHamamji]

Is your feature request related to a problem? Please describe.
It's not a problem, it's a UI/UX suggestion.

Describe the solution you'd like
There could be an option to show the files in a tree instead of a list of paths.
The tree could potentially be interactive (opening and closing directories).

Describe alternatives you've considered
Here are some more details:

• To make it a tree, only the file name should be shown, not the entire path.
• Additional lines should be added for directory names.
• The file and directory names should be properly indented.

Additional context
My recommendation is inspired by VSCode's git integration, here are two screenshots (the first one has a file list, second one has a file tree):

This corresponds to the following file tree (note that unmodified files are hidden in the screenshot above):

.
├── init.lua
├── lazy-lock.json
└── lua
    └── custom
        ├── lazy.lua
        ├── options.lua
        └── plugins
            ├── git.lua
            ├── lsp.lua
            ├── mason.lua
            ├── nvim-cmp.lua
            ├── nvim-tree.lua
            ├── telescope.lua
            ├── theme.lua
            └── treesitter.lua