Add CodeQL platform GitHub workflow

Adds a new GitHub workflow that allows CodeQL to run against platform
builds. Previously, only a "CI" CodeQL workflow existed that did not
support platform builders.

This file is being added directly to the repo as it is paired with
other changes that it has been tested alongside. In the future, it
will automatically be synced from mu_devops.

Nothing about the file is specific to mu_tiano_platforms or any
particular platform. It works by discovering all buildable platforms
in a repo before any dependencies are cloned and then verifying
the build files in the platform package directory support platform
build. If they do, it is checked if they support CodeQL. Only
platforms that meet all of these conditions are actually built via
a dynamic platform package matrix.

This allows the workflow to scale across platform repos and
automatically pick up new platforms as they onboard support for
CodeQL.

Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>