Conditionally create mobile project

[RyanClementsHax]

Is there an existing issue that is already proposing this?

• [X] I have searched the existing issues

Is your feature request related to a problem? Please describe it

Not all mantis apps need a mobile app.

Describe the solution you'd like

mantis-app init --createMobileApp=false should avoid creating a mobile project.

Teachability, documentation, adoption, migration strategy

No response

What is the motivation / use case for changing the behavior?

Not all mantis apps need a mobile project.