feat: Implement Tags feature

[aVolpe]

This implement a basic tag feature.

All tags are stored in a separate key in redis, like the services id.

The /api/report/services method accept a query param with tags to filter the services.

TODO:

• [x] Custom tags per service
• [x] Filter services by tags
• [ ] Improve the appearance
• [ ] Add tags when specific conditions mets, like outages.

ref #56