You can achieve this using a git template directory
git config --global init.templatedir /path/to/template
You can then add files to the folder /path/to/template/hooks and they will be automatically copied to the .git/hooks folder on git init
You can place the .gitignore contents you want in a file you name exclude in the folder /path/to/template/info. Then it will effectively be a .gitignore file in all new repositories created by git init.
Note that the .gitignore file is not populated with the content of exclude. On git init the exclude file in the infofolder will be copied into the .git/info folder of your git repository. This will cause the file patterns listed in exclude to be ignored, just like patterns in .gitignore.
If you are on unix, there is even a default template directory /usr/share/git-core/templates. On MacOS the template directory is in /usr/local/share/git-core/templates