refactor: enable QA tests and jafar self test (#208)

* refactor: enable QA tests and jafar self test

Part of https://github.com/ooni/probe/issues/1335

* chore: make sure all workflows run on release branches

internal/engine/.github/workflows/jafar.yml

@@ -1,14 +0,0 @@
-name: jafar
-on:
-  schedule:
-    - cron: "0 5 * * 3"
-jobs:
-  test:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/setup-go@v1
-        with:
-          go-version: "1.14"
-      - uses: actions/checkout@v2
-      - run: go build -v ./cmd/jafar
-      - run: sudo ./testjafar.bash