Refactor names (#31405)

This PR only does "renaming":

* `Route` should be `Router` (and chi router is also called "router")
* `Params` should be `PathParam` (to distingush it from URL query param, and to match `FormString`)
* Use lower case for private functions to avoid exposing or abusing

routers/api/packages/helm/helm.go

@@ -101,14 +101,14 @@ func Index(ctx *context.Context) {
 
 // DownloadPackageFile serves the content of a package
 func DownloadPackageFile(ctx *context.Context) {
-	filename := ctx.Params("filename")
+	filename := ctx.PathParam("filename")
 
 	pvs, _, err := packages_model.SearchVersions(ctx, &packages_model.PackageSearchOptions{
 		OwnerID: ctx.Package.Owner.ID,
 		Type:    packages_model.TypeHelm,
 		Name: packages_model.SearchValue{
 			ExactMatch: true,
-			Value:      ctx.Params("package"),
+			Value:      ctx.PathParam("package"),
 		},
 		HasFileWithName: filename,
 		IsInternal:      optional.Some(false),