playbookRepos should support a path option

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Is your feature request related to a problem? Currently https://docs.robusta.dev/master/user-guide/additional-playbooks.html#loading-additional-playbooks seems to expect a separate repo for robusta playbooks. This breaks the mono repo approach several companies implement with their codebase, including companies like Google.

Describe the solution you'd like A path option should be added so existing repo can be used without requiring playbooks in root dir

Describe alternatives you've considered Playbooks existing in root dir of existing repo potentially an option but results in things potentially getting messy from a folder structure standpoint

Additional context See linked guide above