Convert the continuous integration process to use GitHub's internal
CI cloud. Allows us to run up to 20 jobs in parallel, speeding up
CI immensely. Keep a short Travis-CI run, too, just for sanity and backup.
Uses new keys and secret when publishing a release to
esp8266.github.io.
* no-op test
* no-op test
* bionic
* missing python package for doc building with bionic
* fix previous commit
* remove external repo for gcc7 (causing issues), it is default under bionic
fix python3-setuptools install
* tryfix git submodule recursive (git 2.21/2.22 ?)
* ci: fix checking for presence of CI_GITHUB_API_KEY
CI_GITHUB_API_KEY is always set when evaluating job include/exclude conditions, and it only gets removed when the job starts. Move the check into the script.
* ci: split build jobs into separate shell scripts