commands: Add TLS/HTTPS support to hugo server

* commands: Add TLS/HTTPS support to hugo server

The "auto cert" handling in this PR is backed by mkcert (see link below).

To get this up and running on a new PC, you can:

```
hugo server trust
hugo server --tlsAuto
```

When `--tlsAuto` (or `--tlsCertFile` and `--tlsKeyFile`) is set and no `--baseURL` is provided as a flag, the server is
started with TLS and `https` as the protocol.

Note that you only need to run `hugo server trust` once per PC.

If you already have the key and the cert file (e.g. by using mkcert directly), you can do:

```
hugo server --tlsCertFile mycert.pem --tlsKeyFile mykey.pem
```

See https://github.com/FiloSottile/mkcert

Fixes #11064

commands/commandeer.go

@@ -18,6 +18,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"log"
 	"os"
 	"os/signal"
 	"path/filepath"
@@ -389,6 +390,9 @@ func (r *rootCommand) PreRun(cd, runner *simplecobra.Commandeer) error {
 	if r.quiet {
 		r.Out = io.Discard
 	}
+	// Used by mkcert (server).
+	log.SetOutput(r.Out)
+
 	r.Printf = func(format string, v ...interface{}) {
 		if !r.quiet {
 			fmt.Fprintf(r.Out, format, v...)