bug(mac): add kmp.inf support

[sgschantz]

Describe the bug

Older Keyman packages that do not include a kmp.json file but only a kmp.inf file should be loaded successfully using Keyman Configuration.

Keyman apps

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

Keyman version

alpha 19