chore: merge probe-engine into probe-cli (#201)

This is how I did it:

1. `git clone https://github.com/ooni/probe-engine internal/engine`

2. ```
(cd internal/engine && git describe --tags)
v0.23.0
```

3. `nvim go.mod` (merging `go.mod` with `internal/engine/go.mod`

4. `rm -rf internal/.git internal/engine/go.{mod,sum}`

5. `git add internal/engine`

6. `find . -type f -name \*.go -exec sed -i 's@/ooni/probe-engine@/ooni/probe-cli/v3/internal/engine@g' {} \;`

7. `go build ./...` (passes)

8. `go test -race ./...` (temporary failure on RiseupVPN)

9. `go mod tidy`

10. this commit message

Once this piece of work is done, we can build a new version of `ooniprobe` that
is using `internal/engine` directly. We need to do more work to ensure all the
other functionality in `probe-engine` (e.g. making mobile packages) are still WAI.

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

internal/engine/QA/probeasn.py

@@ -0,0 +1,88 @@
+#!/usr/bin/env python3
+
+
+""" ./QA/probeasn.py - QA script for the -g miniooni option. """
+
+import contextlib
+import json
+import os
+import shlex
+import shutil
+import socket
+import subprocess
+import sys
+import time
+import urllib.parse
+
+sys.path.insert(0, ".")
+import common
+
+
+def execute_miniooni(ooni_exe, outfile, arguments):
+    """ Executes miniooni and returns the whole measurement. """
+    if "miniooni" not in ooni_exe:
+        return None
+    tmpoutfile = "/tmp/{}".format(outfile)
+    with contextlib.suppress(FileNotFoundError):
+        os.remove(tmpoutfile)  # just in case
+    cmdline = [
+        ooni_exe,
+        arguments,
+        "-o",
+        tmpoutfile,
+        "--home",
+        "/tmp",
+        "example",
+    ]
+    print("exec: {}".format(cmdline))
+    common.execute(cmdline)
+    shutil.copy(tmpoutfile, outfile)
+    result = common.read_result(outfile)
+    assert isinstance(result, dict)
+    assert isinstance(result["test_keys"], dict)
+    return result
+
+
+def probeasn_without_g_option(ooni_exe, outfile):
+    """ Test case where we're not passing to miniooni the -g option """
+    m = execute_miniooni(ooni_exe, outfile, "-n")
+    if m is None:
+        return
+    assert m["probe_cc"] != "ZZ"
+    assert m["probe_ip"] == "127.0.0.1"
+    assert m["probe_asn"] != "AS0"
+    assert m["probe_network_name"] != ""
+    assert m["resolver_ip"] == "127.0.0.2"
+    assert m["resolver_asn"] != "AS0"
+    assert m["resolver_network_name"] != ""
+
+
+def probeasn_with_g_option(ooni_exe, outfile):
+    """ Test case where we're passing the -g option """
+    m = execute_miniooni(ooni_exe, outfile, "-gn")
+    if m is None:
+        return
+    assert m["probe_cc"] != "ZZ"
+    assert m["probe_ip"] == "127.0.0.1"
+    assert m["probe_asn"] == "AS0"
+    assert m["probe_network_name"] == ""
+    assert m["resolver_ip"] == "127.0.0.2"
+    assert m["resolver_asn"] == "AS0"
+    assert m["resolver_network_name"] == ""
+
+
+def main():
+    if len(sys.argv) != 2:
+        sys.exit("usage: %s /path/to/ooniprobelegacy-like/binary" % sys.argv[0])
+    outfile = "probeasn.jsonl"
+    ooni_exe = sys.argv[1]
+    tests = [
+        probeasn_with_g_option,
+        probeasn_without_g_option,
+    ]
+    for test in tests:
+        test(ooni_exe, outfile)
+
+
+if __name__ == "__main__":
+    main()