Add fix to bring back old github feeds

[gautamkrishnar]

Recently GitHub doubled down on releasing algorithmetic feeds to all the users. The feedback about this is, as expected pretty bad: https://github.com/orgs/community/discussions/categories/feed

Even though the homepage feed is replaced the old feed is still available via an API (Until when? we don't know)

This can be parsed and injected to bring back the old feeds.

[gautamkrishnar]

Since there are open source scripts out there that brings back the old GitHub feeds, the users can use it to get back the old feeds: https://github.com/Gerrit0/old-github-feed

I am not interested in investing my time on migrating this extension to manifest v3 and supporting it since GitHub now has sort of built in filtering.