[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

docs/api/swagger.yaml

@@ -268,6 +268,10 @@ definitions:
                     $ref: '#/definitions/emoji'
                 type: array
                 x-go-name: Emojis
+            enable_rss:
+                description: Account has enabled RSS feed.
+                type: boolean
+                x-go-name: EnableRSS
             fields:
                 description: Additional metadata attached to this account's profile.
                 items:
@@ -2576,6 +2580,10 @@ paths:
                   in: formData
                   name: custom_css
                   type: string
+                - description: Enable RSS feed for this account's Public posts at `/[username]/feed.rss`
+                  in: formData
+                  name: enable_rss
+                  type: boolean
             produces:
                 - application/json
             responses: