feat: console help, examples and named loggers (SummerCMS v0.4.0)

Every command gets long help and examples, descriptions in imperative
sentence case, and a warn-only TestCommandsDocumented over bonfire.CheckDocs.
The plugin logs through a diary component logger instead of the process
default logger. Requires SummerCMS v0.4.0; command names and flags unchanged.

plugin.go

@@ -4,7 +4,6 @@ import (
 	"embed"
 	"fmt"
 	"io/fs"
-	"log/slog"
 	"net/http"
 	"strconv"
 	"strings"
@@ -72,7 +71,7 @@ func (p *Plugin) wireSiteCache(app *backpack.App) error {
 		return nil
 	}
 	cfg := app.Config
-	log := slog.Default()
+	log := pluginLog
 	aliasURL := cfg.String(classes.SiteCachePurgeURLKey)
 	aliasToken := cfg.String(classes.SiteCachePurgeTokenKey)
 	aliasSet := strings.TrimSpace(aliasURL) != "" || aliasToken != ""