Proposed Charter draft

My apologies for the late notice, I could have sworn I'd already sent this.

For discussion in the WG meeting:  https://w3c.github.io/immersive-web-wg-
charter/immersive-web-wg-charter.html is the HTML version, here is the
 source  <https://github.com/w3c/immersive-web-wg-charter>if you want to
comment or propose edits, and here is the diff from our current charter
<https://services.w3.org/htmldiff?doc1=https%3A%2F%2Fwww.w3.org%2F2018%2F09%2Fimmersive-web-wg-charter&doc2=https%3A%2F%2Fw3c.github.io%2Fimmersive-web-wg-charter%2Fimmersive-web-wg-charter.html>
.

-Chris