描述你请求的功能是否和问题有关 / Is your feature request related to a problem? Please describe.

Most Japanese speakers use 12-key flick keyboard on mobile devices, which is widely used in like iOS and Google Japanese Input(Mozc) on Android and so on. It would be great to implement the flick keyboard for Japanese input on fcitx5-android in the same way.

描述解决方案 / Describe the solution you'd like

Implement 12-key flick keyboard for Japanese input.

描述替代方案 / Describe alternatives you've considered

None.

附加信息 / Additional context

None.