Enhance swipe up/down, and exploer another caps/shift button behavior

[mishi321]

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.

1. Enhance swipe up/down -> swipe to input uppercase
   Now the fcitx5-android can config the swipe up/down to input symbol, and in actually only one of up/down can be occupied, another one will be vacancy.
   I desired to add new feature to input uppercase with swipe up/down. It can free the caps/shift button in most of
   English input scene(the first letter uppercase) by reduce once click.

2. Another caps/shift button behavior -> 2 mode: lowercase(default), always uppercase(once click)
   Now the fcitx5-android caps/shift button own 3 mode: lowercase(default), once uppercase(once click), always uppercase(long press). I think the always uppercase activate by long press is a bad design to input fast, although it is the most popular design. I hope by enhance swipe to input upppercase can't simplify the caps/shift to bring the better experience.

描述解决方案 / Describe the solution you'd like
The 1st feature is worthy to realize, there is no obvious reasons to against it.
The 2nd feature's reach has the risk to break the user's habits, although I think the old design is bad, but the change may be againsted strongly, so if you don't agree or like this feature you can ignore this feature.
The 1st and 2nd feature are independented.

附加信息 / Additional context
Those two features are all implemented by QQ输入法(android) by default config.
Hope these suggests make fcitx5-android better.