[feat] /services implementation

[lgrd]

Need

We need to know available services, and to manage them.

Tasks

• GET /services. See [feat] GET /services implementation #43
• POST /services
• GET /services/{service}. See [feature] Get /services/:service implementation #49
• PATCH /services/{service}
• DELETE /services/{service}
• GET /services/{service}/restart. See [feat] /services/{service}/restart implementation #45