Linked Series (#1230)

* Implemented the ability to link different series together through Edit Series. CSS pending.

* Fixed up the css for related cards to show the relation

* Working on making all tabs in edit seris modal save in one go. Taking a break.

* Some fixes for Robbie to help with styling on

* Linked series pill, center library

* Centering library detail and related pill spacing

- Library detail cards are now centered if total number of items is > 6 or if mobile.
- Added ability to determine if mobile (viewport width <= 480px
- Fixed related card spacing
- Fixed related card pill spacing

* Updating relation form spacing

* Fixed a bug in card detail layout when there is no pagination, we create one in a way that all items render at once.

* Only auto-close side nav on phones, not tablets

* Fixed a bug where we had flipped state on sideNavCollapsed$

* Cleaned up some misleading comments

* Implemented RBS back in and now  if you have a relationship besides prequel/sequel, the target series will show a link back to it's parent.

* Added Parentto pipe

* Missed a relationship type

Co-authored-by: Robbie Davis <robbie@therobbiedavis.com>

API/Entities/Series.cs

@@ -66,9 +66,18 @@ public class Series : IEntityDate
     public DateTime LastChapterAdded { get; set; }
 
     public SeriesMetadata Metadata { get; set; }
+
     public ICollection<AppUserRating> Ratings { get; set; } = new List<AppUserRating>();
     public ICollection<AppUserProgress> Progress { get; set; } = new List<AppUserProgress>();
 
+    /// <summary>
+    /// Relations to other Series, like Sequels, Prequels, etc
+    /// </summary>
+    /// <remarks>1 to Many relationship</remarks>
+    public virtual ICollection<SeriesRelation> Relations { get; set; } = new List<SeriesRelation>();
+    public virtual ICollection<SeriesRelation> RelationOf { get; set; } = new List<SeriesRelation>();
+
+
     // Relationships
     public List<Volume> Volumes { get; set; }
     public Library Library { get; set; }