Support a .craignore file

[mauleb]

Description

At the moment, everything in the example-react-project is copied into the generated project without exception. It would be of benefit to be able to define a .craignore file within the example repo so that certain files/directories can be excluded. For example, it would be nice to have github templates / changelog / contributing files, but those are specific to the example project and would not be relevant to newly generated ones.

Implementation

• update generator script to look for a .craignore file after cloning the example repo
• loop through glob patterns and delete post clone
• once complete, also delete the .craignore file from the generated project

[joshytaco]

@mauleb Would it be better to just not copy over things that would be defined in the .craignore file, instead of adding that file? We don't have enough content in the example project and that content doesn't change enough to justify having a file that defines what should be ignored, in my opinion.

Additionally, it would make sense to provide something for the user generating the project to decide what to ignore, but I don't think that level of granular choice is necessary or even helpful.