commands: Show server error info in browser

The main item in this commit is showing of errors with a file context when running `hugo server`.

This can be turned off: `hugo server --disableBrowserError` (can also be set in `config.toml`).

But to get there, the error handling in Hugo needed a revision. There are some items left TODO for commits soon to follow, most notable errors in content and config files.

Fixes #5284
Fixes #5290
See #5325
See #5324

tpl/partials/init_test.go

@@ -16,6 +16,7 @@ package partials
 import (
 	"testing"
 
+	"github.com/gohugoio/hugo/common/loggers"
 	"github.com/gohugoio/hugo/deps"
 	"github.com/gohugoio/hugo/tpl/internal"
 	"github.com/stretchr/testify/require"
@@ -28,6 +29,7 @@ func TestInit(t *testing.T) {
 	for _, nsf := range internal.TemplateFuncsNamespaceRegistry {
 		ns = nsf(&deps.Deps{
 			BuildStartListeners: &deps.Listeners{},
+			Log:                 loggers.NewErrorLogger(),
 		})
 		if ns.Name == name {
 			found = true