Enable use of GitHub Actions for dependabot and use of self-hosted runners

## Prerequisites:
[GitHub Dependabot on actions](https://docs.github.com/en/code-security/dependabot/working-with-dependabot/about-dependabot-on-github-actions-runners)
[GitHub Dependabot on self-hosted runners](https://docs.github.com/en/code-security/dependabot/working-with-dependabot/managing-dependabot-on-self-hosted-runners])

## New Feature

I would like to configure in my suborg the use of dependabot in actions and in self hosted runners, you could consider adding it with 2 properties like `enableDependabotInActions` and `enableDependabotInSelfHostedRunners` inside repository.security