Add vi-mode (inspired by ranger)
FEATURE: 94001
Supported functionality:
- Move to trash (`x` or `d`)
- Go home (`gh`)
- Go root (`gr`)
- Paste (`p`)
- Undo (`u`)
- Copy (`y`)
- Move selection up and down (`k` and `j`)
- Go up (`h`)
- Open selected item (`l`)
- Select/deselect files one by one (`+` and `-`)