Rework Observation Lists for the laravel version of DeepskyLog #794

Rework the observation lists for the new version of DeepskyLog. The observers will need to subscribe to the observing lists they are interested in. The observing lists will have a description where you can describe the list. When subscribing to a new observing lists, the lists will be sorted by the number of likes and the number of times the observing lists is used by other observers. The new version will make it easy to share the lists on twitter / facebook / mail / Whatsapp(?) / ...

• Add planets, sun, comets (Make sure that the comets with a slash in their name also can be added (2P/Encke, ...)), ...
• Add link to all observation lists of an observer to the detail page of the observer
• Rethink the observation lists
• Only receive messages about new observing lists if you opt in for this
• In target/show.blade.php
  • Make it possible to change / view the description of the target
  • Add the private / public lists the object belongs to
• Likes / dislikes / ... for public lists: https://github.com/cybercog/laravel-love or https://laravel-news.com/manage-friendships-likes-and-more-with-the-acquaintances-laravel-package
• Sort on highest number of likes, add extra likes when someone subscribes to the observation list. Remove like if someone unsubscribes from the observation list.
• Share observation list on twitter / facebook
• Use Laravel scout (https://github.com/laravel/scout/tree/master) to do full text searching on the description of the observing lists