Summary:
This starts us transitioning the Yoga website off of an ancient version of Gatsby by initializing a new Docusaurus project. This commit adds a new stock project, to be filled in later, then fixes license lint errors.
Note that this seems to have init'd using npm, but in the next diff I convert this to yarn workspaces anyway.
Reviewed By: yungsters
Differential Revision: D46884434
fbshipit-source-id: ee388aa9388b1030dbbf59a73dd1529fee05065c
