fix: remove freenode, point at Matrix lobby

[lidel]

Sadly, Freenode is infested by very inappropriate spam this weekend, and the modes we have on our IRC channels mean users are not able to talk unless they register there.

This PR is a bare minimum to start funneling users to the new lobby (Matrix+Discord) instead, so at least they register into a protocol that future-proofs their access to the lobby.

Closes #786
cc @autonome @TheDiscordian

[TheDiscordian]

Thanks for this 😍

The FileCoin Slack is also integrated into the bridge. Do you think it'd be worth linking that too? Slack info: https://github.com/filecoin-project/community#join-the-community

[lidel]

In effort to decrease noise and funnel users to specific topic areas, we may want to add rooms for libp2p, ipld, multiformats ones to this list.

We also need to have a link for people interested discussing Filecoin (like https://github.com/filecoin-project/community#join-the-community), so less people will join IPFS lobby asking questions about FIL.

[TheDiscordian]

I wonder if it'd be worth just merging libp2p, ipld, and multiformats into #ipfs as I don't typically see a lot of activity in the other rooms. Mostly because while the topic'd rooms are more specific, and ultimately get specialised answers, I worry users might leave before they get their answer if there's little-to-no activity normally.

Definitely agree on linking to the FIL community somewhere. The FIL Slack also recently got IPFS related channels too (which are the ones bridged to the Discord/Matrix rooms).

[TheDiscordian]

Actually scratch that, the rooms #ipld and #libp2p are already live on the super bridge, might as well point people to them.

[johnnymatthews]

Ah that's a shame. This PR looks fine from my end! Haven't ran it through Grammarly because I'm on mobile, but it looks solid enough. Merge when ready.