[Chat] Chat update - added channels for each room

[Scott Bragg]

Hi everyone,

The #linux.conf.au channel has been buzzing with activity during the
week, and with the (actual) conference to start tomorrow, we''ve
expanded our little Matrix experiment and added Freenode, Matrix
and Slack channels for each room:

These are:

   #lca2017_plenary
   #lca2017_tasman_a
   #lca2017_tasman_bc
   #lca2017_wellington_1
   #lca2017_wellington_2
   #lca2017_boardwalk

all on the Freenode network and Slack. On Matrix, add ":matrix.org"
to the end of those channel names.

Now you can use these for discussions related to specific talks,
and the IRC widget on the streaming page also links to these rooms.

We have updated the  summary of these unofficial chat platform options 
on the
conference wiki here:
https://linux.conf.au/wiki/conference/chat/

See you tomorrow,

Scott Bragg and the other Matrix enthusiasts