Post-Substack move stuff

[amyrlam]

• If Substack goes well, close Goodbits account, particularly be sure to end @tylerturdenpants payment (thank you!) as Substack is free.
• If Substack goes well, archive https://github.com/ember-learn/ember-times-tools, is no longer needed. I moved the Twitter / dev.to instructions here
• Amy: Update these instructions next send, 2/5

[amyrlam]

Tagged @tylerturdenpants on Discord and closed out Goodbits!

Archived https://github.com/ember-learn/ember-times-tools repo cc @ijlee2

Will run thru the instructions tmrw and update as needed

[ijlee2]

@amyrlam Much thanks for leading the initiative to migrate the email service!