Fix some RPM registry flaws (#28782)

Related #26984
(https://github.com/go-gitea/gitea/pull/26984#issuecomment-1889588912)

Fix admin cleanup message.
Fix models `Get` not respecting default values.
Rebuild RPM repository files after cleanup.
Do not add RPM group to package version name.
Force stable sorting of Alpine/Debian/RPM repository data.
Fix missing deferred `Close`.
Add tests for multiple RPM groups.
Removed non-cached `ReplaceAllStringRegex`.

If there are multiple groups available, it's stated in the package
installation screen:

![grafik](8f132760-882c-4ab8-9678-77e47dfc4415)

models/packages/package_file.go

@@ -46,18 +46,18 @@ type PackageFile struct {
 func TryInsertFile(ctx context.Context, pf *PackageFile) (*PackageFile, error) {
 	e := db.GetEngine(ctx)
 
-	key := &PackageFile{
-		VersionID:    pf.VersionID,
-		LowerName:    pf.LowerName,
-		CompositeKey: pf.CompositeKey,
-	}
+	existing := &PackageFile{}
 
-	has, err := e.Get(key)
+	has, err := e.Where(builder.Eq{
+		"version_id":    pf.VersionID,
+		"lower_name":    pf.LowerName,
+		"composite_key": pf.CompositeKey,
+	}).Get(existing)
 	if err != nil {
 		return nil, err
 	}
 	if has {
-		return pf, ErrDuplicatePackageFile
+		return existing, ErrDuplicatePackageFile
 	}
 	if _, err = e.Insert(pf); err != nil {
 		return nil, err
@@ -93,13 +93,13 @@ func GetFileForVersionByName(ctx context.Context, versionID int64, name, key str
 		return nil, ErrPackageFileNotExist
 	}
 
-	pf := &PackageFile{
-		VersionID:    versionID,
-		LowerName:    strings.ToLower(name),
-		CompositeKey: key,
-	}
+	pf := &PackageFile{}
 
-	has, err := db.GetEngine(ctx).Get(pf)
+	has, err := db.GetEngine(ctx).Where(builder.Eq{
+		"version_id":    versionID,
+		"lower_name":    strings.ToLower(name),
+		"composite_key": key,
+	}).Get(pf)
 	if err != nil {
 		return nil, err
 	}