Change to default .gitignore file for Spring

Build files are still being tracked despite including "build/" in the .gitignore. The files were originally added to master, so we all need to clear the cache in git on any machines that cloned the original repository.

We will all need to do this, so it may be best to do it together to ensure we aren't committing build files.

The .gitignore is also not the default for Spring projects. We should stick to that to make sure we don't have this issue again.

I've assigned a weight of 1 because we will need to make sure it is working correctly on multiple machines.