scanning and poster improvements (#24)

* first pass at refresh-all-metadata by source

* add version to startup logs

* lock media source during refresh

* fix local media source "name" in collection editor

* optimize scanning so playouts only rebuild when necessary

* support more poster file types

* more scanning improvements; check for missing posters during scans

ErsatzTV.Infrastructure/Data/Repositories/MediaCollectionRepository.cs

@@ -85,15 +85,18 @@ namespace ErsatzTV.Infrastructure.Data.Repositories
             return _dbContext.SaveChangesAsync();
         }
 
-        public async Task InsertOrIgnore(TelevisionMediaCollection collection)
+        public async Task<bool> InsertOrIgnore(TelevisionMediaCollection collection)
         {
             if (!_dbContext.TelevisionMediaCollections.Any(
                 existing => existing.ShowTitle == collection.ShowTitle &&
                             existing.SeasonNumber == collection.SeasonNumber))
             {
                 await _dbContext.TelevisionMediaCollections.AddAsync(collection);
-                await _dbContext.SaveChangesAsync();
+                return await _dbContext.SaveChangesAsync() > 0;
             }
+
+            // no change
+            return false;
         }
 
         public Task<Unit> ReplaceItems(int collectionId, List<MediaItem> mediaItems) =>

ErsatzTV.Infrastructure/Data/Repositories/MediaItemRepository.cs

@@ -97,10 +97,10 @@ LIMIT {0} OFFSET {1}",
                 .Filter(i => i.MediaSourceId == mediaSourceId)
                 .ToListAsync();
 
-        public async Task Update(MediaItem mediaItem)
+        public async Task<bool> Update(MediaItem mediaItem)
         {
             _dbContext.MediaItems.Update(mediaItem);
-            await _dbContext.SaveChangesAsync();
+            return await _dbContext.SaveChangesAsync() > 0;
         }
 
         public async Task Delete(int mediaItemId)