Stash rating system (#2830)

* add rating100 fields to represent rating range 1-100
* deprecate existing (1-5) rating fields
* add half- and quarter-star options for rating system
* add decimal rating system option

Co-authored-by: WithoutPants <53250216+WithoutPants@users.noreply.github.com>

pkg/models/model_image.go

@@ -14,11 +14,12 @@ import (
 type Image struct {
 	ID int `json:"id"`
 
-	Title     string `json:"title"`
-	Rating    *int   `json:"rating"`
-	Organized bool   `json:"organized"`
-	OCounter  int    `json:"o_counter"`
-	StudioID  *int   `json:"studio_id"`
+	Title string `json:"title"`
+	// Rating expressed in 1-100 scale
+	Rating    *int `json:"rating"`
+	Organized bool `json:"organized"`
+	OCounter  int  `json:"o_counter"`
+	StudioID  *int `json:"studio_id"`
 
 	// transient - not persisted
 	Files         RelatedImageFiles
@@ -113,7 +114,8 @@ type ImageCreateInput struct {
 }
 
 type ImagePartial struct {
-	Title     OptionalString
+	Title OptionalString
+	// Rating expressed in 1-100 scale
 	Rating    OptionalInt
 	Organized OptionalBool
 	OCounter  OptionalInt