Add more linters to improve code readability (#19989)

Add nakedret, unconvert, wastedassign, stylecheck and nolintlint linters to improve code readability

- nakedret - https://github.com/alexkohler/nakedret - nakedret is a Go static analysis tool to find naked returns in functions greater than a specified function length.
- unconvert - https://github.com/mdempsky/unconvert - Remove unnecessary type conversions
- wastedassign - https://github.com/sanposhiho/wastedassign -  wastedassign finds wasted assignment statements.
- notlintlint -  Reports ill-formed or insufficient nolint directives
- stylecheck - https://staticcheck.io/docs/checks/#ST - keep style consistent
  - excluded: [ST1003 - Poorly chosen identifier](https://staticcheck.io/docs/checks/#ST1003) and [ST1005 - Incorrectly formatted error string](https://staticcheck.io/docs/checks/#ST1005)

services/migrations/onedev.go

@@ -38,7 +38,7 @@ func (f *OneDevDownloaderFactory) New(ctx context.Context, opts base.MigrateOpti
 		return nil, err
 	}
 
-	repoName := ""
+	var repoName string
 
 	fields := strings.Split(strings.Trim(u.Path, "/"), "/")
 	if len(fields) == 2 && fields[0] == "projects" {