Add super-linter as GitHub action

Add [`super-linter` as GitHub action](https://github.com/super-linter/super-linter). See the sample configuration for the [`unikraft/docs` repository](https://unikraft.org/docs/contributing/docs#using-the-linter) and for the [`sandblaster` repository](https://github.com/malus-security/sandblaster/blob/master/.github/workflows/linter.yml).