Migrate the Google Group to this repository

[brettfiedler]

Transferred from https://github.com/phetsims/community/issues/5

@samreid and I met to begin the transfer process. We restricted posting access. We changed the description and welcome post to reflect the redirect.

We decided we should verify that phetsims/community would be moving to scenerystack/community. @emily-phet, @samreid, and @brettfiedler agreed we should make the switch.

@brettfiedler is copying over issues and information from phetsims/community so we can reuse phetsims/community for future simulation focused community discussion.

Next steps:

• [ ] Update scenerystack.org to redirect to this repository
• [x] Copy over files
• [x] Copy over relevant issues
• [x] Create Discussions Board
• [x] Copy Welcome post and Breaking changes post to new Discussions board
• [x] Update links in Google Group post to scenerystack.org
• [x] Make Google Group post

[brettfiedler]

@samreid and @brettfiedler closed down posting permissions to the Google group and made a final post. https://groups.google.com/g/developing-interactive-simulations-in-html5/c/CyJPJoXnNv0

We also added a message to the Breaking Changes thread. https://groups.google.com/g/developing-interactive-simulations-in-html5/c/1Zm4l3sye20

Before closing, I'd like to see the Scenerystack.org redirect changed.

[brettfiedler]

Redirect completed last week!