FIX: Quoting local dates bbcode regeneration (#17141)

This commit allows quoting of discourse-local-date elements
and converts the quoted tags back into bbcode so that the
rendered quote will also render the discourse-local-date HTML.
This works on single dates as well as date ranges, and supports
all of the options used by discourse-local-date.

This also necessitated adding addTextDecorateCallback to the
to-markdown core lib (similar to addBlockDecorateCallback and
addTagDecorateCallback) to transform the text nodes between
date ranges to remove the -> in the final quote.

c.f. https://meta.discourse.org/t/quotes-that-contain-date-time/101999

plugins/discourse-local-dates/assets/javascripts/lib/local-date-markup-generator.js

@@ -0,0 +1,58 @@
+import { isEmpty } from "@ember/utils";
+
+export default function generateDateMarkup(
+  fromDateTime,
+  options,
+  isRange,
+  toDateTime
+) {
+  let text = ``;
+
+  if (isRange) {
+    let from = [fromDateTime.date, fromDateTime.time]
+      .filter((element) => !isEmpty(element))
+      .join("T");
+    let to = [toDateTime.date, toDateTime.time]
+      .filter((element) => !isEmpty(element))
+      .join("T");
+    text += `[date-range from=${from} to=${to}`;
+  } else {
+    text += `[date=${fromDateTime.date}`;
+  }
+
+  if (fromDateTime.time && !isRange) {
+    text += ` time=${fromDateTime.time}`;
+  }
+
+  if (fromDateTime.format && fromDateTime.format.length) {
+    text += ` format="${fromDateTime.format}"`;
+  }
+
+  if (options.timezone) {
+    text += ` timezone="${options.timezone}"`;
+  }
+
+  if (options.countdown) {
+    text += ` countdown="${options.countdown}"`;
+  }
+
+  if (options.displayedTimezone) {
+    text += ` displayedTimezone="${options.displayedTimezone}"`;
+  }
+
+  if (options.timezones && options.timezones.length) {
+    if (Array.isArray(options.timezones)) {
+      text += ` timezones="${options.timezones.join("|")}"`;
+    } else {
+      text += ` timezones="${options.timezones}"`;
+    }
+  }
+
+  if (options.recurring && !isRange) {
+    text += ` recurring="${options.recurring}"`;
+  }
+
+  text += `]`;
+
+  return text;
+}