Multiple scene URLs (#3852)

* Add URLs scene relationship
* Update unit tests
* Update scene edit and details pages
* Update scrapers to use urls
* Post-process scenes during query scrape
* Update UI for URLs
* Change urls label

pkg/sliceutil/collections.go

@@ -2,6 +2,53 @@ package sliceutil
 
 import "reflect"
 
+// Exclude removes all instances of any value in toExclude from the vs
+// slice. It returns the new or unchanged slice.
+func Exclude[T comparable](vs []T, toExclude []T) []T {
+	var ret []T
+	for _, v := range vs {
+		if !Include(toExclude, v) {
+			ret = append(ret, v)
+		}
+	}
+
+	return ret
+}
+
+func Index[T comparable](vs []T, t T) int {
+	for i, v := range vs {
+		if v == t {
+			return i
+		}
+	}
+	return -1
+}
+
+func Include[T comparable](vs []T, t T) bool {
+	return Index(vs, t) >= 0
+}
+
+// IntAppendUnique appends toAdd to the vs int slice if toAdd does not already
+// exist in the slice. It returns the new or unchanged int slice.
+func AppendUnique[T comparable](vs []T, toAdd T) []T {
+	if Include(vs, toAdd) {
+		return vs
+	}
+
+	return append(vs, toAdd)
+}
+
+// IntAppendUniques appends a slice of values to the vs slice. It only
+// appends values that do not already exist in the slice. It returns the new or
+// unchanged slice.
+func AppendUniques[T comparable](vs []T, toAdd []T) []T {
+	for _, v := range toAdd {
+		vs = AppendUnique(vs, v)
+	}
+
+	return vs
+}
+
 // SliceSame returns true if the two provided lists have the same elements,
 // regardless of order. Panics if either parameter is not a slice.
 func SliceSame(a, b interface{}) bool {