Having OpenAPI is not enough to render sdk/cli/etc. A metadata is
necessary describing path to the spec, operation definition in the spec
and what and how to generate out of it. While most of the data can be
"assumed" there are cases where customization is necessary.
For now add metadata into the tree.
Change-Id: Ice129db1ceb2487c95d4c66946c6a0f57c60824e
6e297814f9