Add FreshRSS widget (#1377)

* feat: add FreshRSS widget

* refactor: revert credentialed.js

* refactor: custom proxy handler for FreshRSS

* refactor: cache the token as long as possible

During installation, the salt is generated and remains constant unless
the user re-installs the FreshRSS instance.

src/widgets/widgets.js

@@ -12,6 +12,7 @@ import downloadstation from "./downloadstation/widget";
 import emby from "./emby/widget";
 import fileflows from "./fileflows/widget";
 import flood from "./flood/widget";
+import freshrss from "./freshrss/widget";
 import ghostfolio from "./ghostfolio/widget"
 import gluetun from "./gluetun/widget";
 import gotify from "./gotify/widget";
@@ -90,6 +91,7 @@ const widgets = {
   emby,
   fileflows,
   flood,
+  freshrss,
   ghostfolio,
   gluetun,
   gotify,