ci: automated edge releases

[laurentsenta]

• Add release workflows to publish binaries & docker images

How to get testground latest (instead of building from scratch)

DOWNLOAD_URL=`curl -s https://api.github.com/repos/laurentsenta/testground/releases/latest \
	| jq '.assets[] | select(.name | test("^.*amd64.tar.gz$")) | .browser_download_url' -r`
wget "${DOWNLOAD_URL}" -O testground.tar.gz
tar -xvzf testground.tar.gz
./testground

Tasks

• [x] add publish docker images & binary on merge to master
• [ ] disable config changes for this test & make envs permanent (use iptestground dockerhub)