Add a test suite ✅

This adds a test suite to be executed using `linuxkit/rtf`.
This is installed in the top-level Makefile

The tests are written in shell script and cover the following cases:

- Kernel Config is OK!
- Kernel Modules can be built and loaded
- QEMU can build and run kernel+initrd, iso-bios and iso-uefi
- That we can build for all other supported output formats
- That all of the examples in `./examples` can be built
- The LTP tests can be run (if `-l slow` is provided)

The virtsock and docker-bench tests were migrated but no test has been
written as yet as AFAICT they are still a WIP

Signed-off-by: Dave Tucker <dt@docker.com>

test/cases/010_platforms/000_qemu/group.sh

@@ -0,0 +1,35 @@
+#!/bin/sh
+# SUMMARY: Linuxkit Qemu Tests
+# LABELS:
+
+# Source libraries. Uncomment if needed/defined
+#. "${RT_LIB}"
+#. "${RT_PROJECT_ROOT}/_lib/lib.sh"
+
+group_init() {
+    # Group initialisation code goes here
+    return 0
+}
+
+group_deinit() {
+    # Group de-initialisation code goes here
+    return 0
+}
+
+CMD=$1
+case $CMD in
+init)
+    group_init
+    res=$?
+    ;;
+deinit)
+    group_deinit
+    res=$?
+    ;;
+*)
+    res=1
+    ;;
+esac
+
+exit $res
+