Support regenerating existing projects

[bkeryan]

Problem to Solve

ni-measurementlink-generator is currently a one-time process: you run it, it generates code, you customize the code, and you check the code into version control.

When NI makes changes to the codegen templates, the process for updating existing projects is to generate a new project and manually copy the updated output.

Proposed Solution

The copier package supports regenerating existing projects from an updated template based on an answers file. NI uses copier for internal project templates. We should consider using it for ni-measurementlink-generator as well.

Cc: @mshafer-NI

AB#2435177