Install tool already sets it as the default so we can just update example ini and docs to it. Fixes: https://github.com/go-gitea/gitea/issues/11081
* Rename custom/conf/app.ini.sample to custom/conf/app.sample.ini for better syntax light on editor * rename to app.example.ini * per @6543 's comment, update all references on docs Co-authored-by: techknowlogick <techknowlogick@gitea.io>