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/config/ids.ts

@@ -20,7 +20,6 @@ export const ids = {
     mentorshipGoalForum:    "1400629118110011526",
     mentorshipProjectForum: "1400616702265266186",
     naomiDiscussionForum:   "1408154690121633917",
-    news:                   "1407804798677418198",
     partnershipRequests:    "1451009066355654829",
     policyIdeation:         "1417294974046965842",
     pressInquiries:         "1451011543482368163",