Create .editorconfig template

Like #1, the template should at least cover coala core and bears

• https://github.com/coala/coala/blob/master/.editorconfig
• https://github.com/coala/coala-bears/issues/2103
• https://github.com/coala/coala-bears/pull/2234
• https://github.com/coala/coala-emacs/issues/21
• https://github.com/coala/docker-coala-base/issues/247
• https://github.com/coala/corobo/issues/331

etc.