Make keys follow Vim's mapping

Using an azerty keyboard, I remapped all the numbers to be like qwerty. However, it doesn't work with Startify that follows original keyboard mapping of numbers. I think it would be better if Startify would follow user's own mappings instead of having its own, as it forces you to remember two sets of keys. Maybe an option to deactivate that if people prefer the original behavior.

Start by examining Startify's existing number-key mappings and how Vim user mappings are resolved. Compare the plugin's behavior with a remapped number key on an azerty keyboard, then determine whether following user mappings or adding an opt-out setting is appropriate. Done means the chosen behavior works consistently without requiring two key layouts.

Written by the indexing model from the issue text.