feat: add defaultDateType config

quartz/cfg.ts

@@ -1,3 +1,4 @@
+import { ValidDateType } from "./components/Date"
 import { QuartzComponent } from "./components/types"
 import { PluginTypes } from "./plugins/types"
 import { Theme } from "./util/theme"
@@ -22,6 +23,8 @@ export interface GlobalConfiguration {
   analytics: Analytics
   /** Glob patterns to not search */
   ignorePatterns: string[]
+  /** Whether to use created, modified, or published as the default type of date */
+  defaultDateType: ValidDateType
   /** Base URL to use for CNAME files, sitemaps, and RSS feeds that require an absolute URL.
    *   Quartz will avoid using this as much as possible and use relative URLs most of the time
    */