META: Convert travis CI commands to circle-ci

[jrconlin]

Travis is not being super reliable right now. Circle-ci is.

Convert the following to circle-ci:

• autopush (skip/deprioritize converting autopush for now in hopes we move to autoendpoint rust instead)
• autopush-rs
• pushbox
• megaphone
• channelserver
• slog-mozlog-json
• common-rs (or maybe get rid of it entirely?)