Part of https://github.com/ooni/probe/issues/1466. We're building both `arm64` and `amd64`. We are still not publishing `arm64` packages, which is what is asked in the original issue, but we're really close to doing that.
This PR groups misc cleanup and changes from https://github.com/ooni/probe-cli/pull/331.
* CLI/linux/build: add documentation
* debian/.gitignore: ignore generated files
* debian/TODO: unnecessary at this point
* debian/ooniprobe-cli.service: remove commented out lines
* debian/rules: remove unnecessary actions
* make: reindent and fix spelling
* smoketest.sh: don't run in verbose mode
Part of https://github.com/ooni/probe/issues/1466
* refactor: build miniooni from toplevel
Of course, also move the specific test checking whether we are
still able of building miniooni.
Part of https://github.com/ooni/probe/issues/1335
* build for current branch just to confirm
* fix: correct the path where linux/arm binary is
* okay, it works, we can remove the special rule
* Use ooni/probe-engine 0.16.0
* Update all the other dependencies
* Use GitHub Actions rather than Travis CI
* Automatically build and test binaries on the target OS (for Windows, macOS, Linux on amd64)
* Make sure we correctly measure coverage
* Make sure we use `-race` when running tests
* Remove unnecessary scripts
* Make sure the README is up-to-date
* Write small script to update binary data and add GitHub Actions checks for it
* Notice that we needed to run ./updatebindata.sh and run it
* Self documenting instructions regarding cross compiling
* Set version number to v3.0.7-beta
Part of https://github.com/ooni/probe-engine/issues/748
