feat(developer): Add Linux support for Keyman Developer

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

Apologies in advance if this is a duplicate, I searched pages upon pages of issues but couldn't find an existing issue.

I am a Linux user who wishes to develop a layout using Keyman. Unfortunately, running the Windows app using Wine results in an unusable app. On every start, the app complains about a broken Unicode character map database, then it either shows a black, blank window or displays a window in which nothing can be clicked except the menu bar.

### Describe the solution you'd like

Native Linux compatibility for the Developer app.

### Describe alternatives you've considered

N/A

### Related issues

N/A

### Keyman apps

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

### Keyman version

N/A

### Operating system

Arch Linux

### Device

HP Envy Laptop 16-h1xxx

### Target application

N/A

### Browser

N/A

### Keyboard name

N/A

### Keyboard version

N/A

### Language name

N/A

### Additional context

N/A