more updates for complex i3 layouts etc.

added mostly serious tl;dr. gotta think about what I want this post to
be -- I've added a bunch of *other* clever things which aren't exclusive
to layouts & autostarting like $i3_home and $i3_msg.
start on fixing-alsa-issues

Hopefully this will be worth it -- copying a *bit* much from Arch Wiki
atm. But still, I'm learning by explaining it for others. And honestly,
the layout isn't perfect on Arch Wiki, though I'm not sure I should
change it ;~;