[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/lib/api/user.js

@@ -49,7 +49,7 @@ module.exports = function ({ apiCall, getChanges }) {
 		},
 
 		updateProfile: function updateProfile() {
-			const formKeys = ["display_name", "locked", "source", "custom_css", "source.note"];
+			const formKeys = ["display_name", "locked", "source", "custom_css", "source.note", "enable_rss"];
 			const renamedKeys = {
 				"source.note": "note"
 			};