New: Add tag support to indexers

(cherry picked from commit c3d54b312ef18b837d54605ea78f1a263fd6900b)

src/NzbDrone.Core/IndexerSearch/ReleaseSearchService.cs

@@ -112,6 +112,9 @@ namespace NzbDrone.Core.IndexerSearch
                 _indexerFactory.InteractiveSearchEnabled() :
                 _indexerFactory.AutomaticSearchEnabled();
 
+            // Filter indexers to untagged indexers and indexers with intersecting tags
+            indexers = indexers.Where(i => i.Definition.Tags.Empty() || i.Definition.Tags.Intersect(criteriaBase.Author.Tags).Any()).ToList();
+
             var reports = new List<ReleaseInfo>();
 
             _logger.ProgressInfo("Searching indexers for {0}. {1} active indexers", criteriaBase, indexers.Count);