Add a SysdiagnoseInfo module to check-sysdiagnose (#917)

* Add a SysdiagnoseInfo module to check-sysdiagnose

check-sysdiagnose had no module of its own: it prepared the archive for
plugin modules and refused to run without one. SysdiagnoseInfo is the
first built-in module. It writes sysdiagnose_info.json with details
about the device and the archive: product type and model, iOS version
and build, serial number, IMEI, MEID and UDID from remotectl_dumpstate.txt
and the mobile activation request, the Apple account name and email from
the App Store daemon database, and the archive's original file name and
creation time from sysdiagnose.log. The build is checked against the
known iOS versions the way BackupInfo does.

The App Store database is copied out of the archive together with its
-wal and -shm sidecars before it is opened, so rows still in the
write-ahead log are read.

With a built-in module the command's list is never empty, so the "no
custom modules" error and its test go. The module joins
IOS_CHECK_IOCS_MODULES like every other module that writes a results
file.

* Note that newer sysdiagnoses lack the App Store daemon database

* Keep refusing check-sysdiagnose runs without a custom module

* Warn instead of refusing when no forensic sysdiagnose module is loaded

tests/test_check_ios_sysdiagnose.py

@@ -1,3 +1,5 @@
+import logging
+
 from click.testing import CliRunner
 
 from mvt.ios.cli import check_sysdiagnose
@@ -50,8 +52,13 @@ def test_check_sysdiagnose_runs_explicitly_scoped_custom_module(tmp_path):
     assert (output_path / "custom_sysdiagnose_module.json").exists()
 
 
-def test_check_sysdiagnose_requires_an_explicitly_scoped_module(tmp_path):
-    result = CliRunner().invoke(check_sysdiagnose, [str(_create_sysdiagnose_folder(tmp_path))])
+def test_check_sysdiagnose_warns_without_a_custom_module(tmp_path, caplog):
+    # The built-in SysdiagnoseInfo alone performs no check, so the run goes
+    # ahead but says so.
+    with caplog.at_level(logging.WARNING, logger="mvt"):
+        result = CliRunner().invoke(
+            check_sysdiagnose, [str(_create_sysdiagnose_folder(tmp_path))]
+        )
 
-    assert result.exit_code != 0
-    assert "No custom modules support mvt-ios check-sysdiagnose" in result.output
+    assert result.exit_code == 0
+    assert "No forensic sysdiagnose modules have been loaded" in caplog.text