Allow options for local configuration

[Max Mehl]

It could be helpful to add options like --preserve-remote on a domain level in the files.

Options:

• File-level, e.g. a comment
• Per-domain level, so a certain key in the YAML (conflicts!)

[Max Mehl]

Idea: add an option key under the domain, e.g. --options. This is an illegal subdomain because it starts with a dash.

This would be on a per-domain level.