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/admin/stacktrace.go

@@ -40,7 +40,7 @@ func Stacktrace(ctx *context.Context) {
 
 // StacktraceCancel cancels a process
 func StacktraceCancel(ctx *context.Context) {
-	pid := ctx.Params("pid")
+	pid := ctx.PathParam("pid")
 	process.GetManager().Cancel(process.IDType(pid))
 	ctx.JSONRedirect(setting.AppSubURL + "/admin/monitor/stacktrace")
 }