Roboleaf product configuration runner

The application rbcrun executes Starlark scripts that define Android product configurations.
See README.md for details.

Test: go test
Fixes: 180529448
Change-Id: I7d728b47d3f381b7052a0d7d51c9e698e5c2e316

tools/rbcrun/testdata/module1.star

@@ -0,0 +1,7 @@
+# Module loaded my load.star
+load("assert.star", "assert")
+
+# Make sure that builtins are defined for the loaded module, too
+assert.true(rblf_file_exists("module1.star"))
+assert.true(not rblf_file_exists("no_such file"))
+test = "module1"