[feature] Add opt-in RSS feed for account's latest Public posts (#897)

* start adding rss functionality

* add gorilla/feeds dependency

* first bash at building rss feed
still needs work, this is an interim commit

* tidy up a bit

* add publicOnly option to GetAccountLastPosted

* implement rss endpoint

* fix test

* add initial user docs for rss

* update rss logo

* docs update

* add rssFeed to frontend

* feed -> feed.rss

* enableRSS

* increase rss logo size a lil bit

* add rss toggle

* move emojify to text package

* fiddle with rss feed formatting

* add Text field to test statuses

* move status to rss item to typeconverter

* update bun schema for enablerss

* simplify 304 checking

* assume account not rss

* update tests

* update swagger docs

* allow more characters in title, trim nicer

* update last posted to be more consistent

web/source/settings/user/profile.js

@@ -96,7 +96,11 @@ module.exports = function UserProfile() {
 			/>
 			<Checkbox
 				id="locked"
-				name="Manually approve follow requests? "
+				name="Manually approve follow requests"
+			/>
+			<Checkbox
+				id="enable_rss"
+				name="Enable RSS feed of Public posts"
 			/>
 			{ !allowCustomCSS ? null :  
 				<TextArea