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/web/repo/attachment.go

@@ -154,5 +154,5 @@ func ServeAttachment(ctx *context.Context, uuid string) {
 
 // GetAttachment serve attachments
 func GetAttachment(ctx *context.Context) {
-	ServeAttachment(ctx, ctx.Params(":uuid"))
+	ServeAttachment(ctx, ctx.PathParam(":uuid"))
 }