Update Chat page for Libera.Chat
Update Chat page for Libera.Chat

`##catholic` seems to have moved off Freenode and on to Libera.Chat.
This commit updates the page at
<https://www.opensourcecatholic.com/chat/> to account for those changes.

- Changed the iframe height so you can see the bottom of the `Start`
  button.
- Updated all freenode links to libera.chat.
- Added specific info to connect to `irc.libera.chat` if not using the
  web client.

opensourcecatholic/opensourcecatholic.github.io,opensourcecatholic/opensourcecatholic.github.io