chore: remove news feed feature (#17)

## Summary

- Removes the hourly RSS news posting scheduler and `postNews` module
- Removes the `rss.ts` interface and `lastRssItems` tracking from the `Amari` interface and bot initialisation
- Removes the `news` channel ID from `ids.ts`
- Removes the `rss-parser` dependency

✨ This PR was created with help from Hikari~ 🌸

Co-authored-by: Naomi Carrigan <commits@nhcarrigan.com>
Reviewed-on: #17
Co-authored-by: Hikari <hikari@nhcarrigan.com>
Co-committed-by: Hikari <hikari@nhcarrigan.com>

src/interfaces/amari.ts

@@ -8,12 +8,8 @@ import type { Client } from "discord.js";
 import type { App } from "octokit";
 
 export interface Amari {
-  discord:      Client;
-  github:       App["octokit"];
-  githubApp:    App;
-  lastRssItems: {
-    freeCodeCamp: string | null;
-    hackerNews:   string | null;
-  };
+  discord:                Client;
+  github:                 App["octokit"];
+  githubApp:              App;
   recentlyActiveChannels: Set<string>;
 }