feat: Distinguish left and right [Shift]

### Is your feature request related to a problem? Please describe.

The developer app only has the option to distinguish left and right Ctrl/Alt. It would be much appreciated if Shift also had a left and right distinction.

### Describe the solution you'd like

Left Shift opens its own set of characters and so does Right Shift. Left Shift and Right Shift would be their separate characters on top of the main one. Just like with the left and right Ctrl/Alt keys.

### Describe alternatives you've considered

_No response_

### Related issues

_No response_

### Keyman apps

- [X] Keyman for Android
- [X] Keyman for iPhone and iPad
- [X] Keyman for Linux
- [X] Keyman for macOS
- [X] Keyman for Windows
- [X] Keyman Developer
- [X] KeymanWeb
- [X] Other - give details at bottom of form

### Keyman version

_No response_

### Operating system

_No response_

### Device

_No response_

### Target application

_No response_

### Browser

_No response_

### Keyboard name

_No response_

### Keyboard version

_No response_

### Language name

_No response_

### Additional context

_No response_