Add filesystem based blob storage (#3187)

* Refactor transaction hooks. Add preCommit
* Add BlobStore
* Use blobStore for tag images
* Use blobStore for studio images
* Use blobStore for performer images
* Use blobStore for scene covers
* Don't generate screenshots in legacy directory
* Run post-hooks outside original transaction
* Use blobStore for movie images
* Remove unnecessary DestroyImage methods
* Add missing filter for scene cover
* Add covers to generate options
* Add generate cover option to UI
* Add screenshot migration
* Delete thumb files as part of screenshot migration

pkg/sqlite/sql.go

@@ -1,9 +1,6 @@
 package sqlite
 
 import (
-	"context"
-	"database/sql"
-	"errors"
 	"fmt"
 	"math/rand"
 	"regexp"
@@ -290,28 +287,6 @@ func getCountCriterionClause(primaryTable, joinTable, primaryFK string, criterio
 	return getIntCriterionWhereClause(lhs, criterion)
 }
 
-func getImage(ctx context.Context, tx dbWrapper, query string, args ...interface{}) ([]byte, error) {
-	rows, err := tx.Queryx(ctx, query, args...)
-
-	if err != nil && !errors.Is(err, sql.ErrNoRows) {
-		return nil, err
-	}
-	defer rows.Close()
-
-	var ret []byte
-	if rows.Next() {
-		if err := rows.Scan(&ret); err != nil {
-			return nil, err
-		}
-	}
-
-	if err := rows.Err(); err != nil {
-		return nil, err
-	}
-
-	return ret, nil
-}
-
 func coalesce(column string) string {
 	return fmt.Sprintf("COALESCE(%s, '')", column)
 }