Clarify path param naming (#32969)

In history (from some legacy frameworks), both `:name` and `name` are
supported as path path name, `:name` is an alias to `name`.

To make code consistent, now we should only use `name` but not `:name`.

Also added panic check in related functions to make sure the name won't
be abused in case some downstreams still use them.

routers/web/auth/oauth.go

@@ -34,7 +34,7 @@ import (
 
 // SignInOAuth handles the OAuth2 login buttons
 func SignInOAuth(ctx *context.Context) {
-	provider := ctx.PathParam(":provider")
+	provider := ctx.PathParam("provider")
 
 	authSource, err := auth.GetActiveOAuth2SourceByName(ctx, provider)
 	if err != nil {
@@ -73,7 +73,7 @@ func SignInOAuth(ctx *context.Context) {
 
 // SignInOAuthCallback handles the callback from the given provider
 func SignInOAuthCallback(ctx *context.Context) {
-	provider := ctx.PathParam(":provider")
+	provider := ctx.PathParam("provider")
 
 	if ctx.Req.FormValue("error") != "" {
 		var errorKeyValues []string