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)

routers/api/v1/utils/hook.go

@@ -133,7 +133,7 @@ func addHook(ctx *context.APIContext, form *api.CreateHookOption, orgID, repoID
 			BranchFilter: form.BranchFilter,
 		},
 		IsActive: form.Active,
-		Type:     webhook.HookType(form.Type),
+		Type:     form.Type,
 	}
 	if w.Type == webhook.SLACK {
 		channel, ok := form.Config["channel"]