.pytool/CISettings: Enable CodeQL audit mode

Since a large number of CodeQL queries are being enabled to identify
issues that the community can collectively resolve, audit mode needs to
be enabled to prevent the build from failing.

In the future, this global audit mode can be disabled and individual
packages can enable/disable audit mode in their package CI YAML file
using the instructions in the CodeQL plugin readme.

Cc: Sean Brogan <sean.brogan@microsoft.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>
Reviewed-by: Sean Brogan <sean.brogan@microsoft.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>
Acked-by: Michael D Kinney <michael.d.kinney@intel.com>

.pytool/CISettings.py

@@ -196,6 +196,12 @@ class Settings(CiBuildSettingsManager, UpdateSettingsManager, SetupSettingsManag
 
             try:
                 scopes += codeql_helpers.get_scopes(self.codeql)
+
+                if self.codeql:
+                    shell_environment.GetBuildVars().SetValue(
+                        "STUART_CODEQL_AUDIT_ONLY",
+                        "TRUE",
+                        "Set in CISettings.py")
             except NameError:
                 pass