Add meta title and description for categories

[devidash]

Add meta title and description for categories
Add meta title, meta keywords, and meta description to products
Update the Upgrader to pull meta data from previous versions of Loaded

--- Want to back this issue? **[Post a bounty on it!](https://www.bountysource.com/issues/26814999-add-meta-title-and-description-for-categories?utm_campaign=plugin&utm_content=tracker%2F40949&utm_medium=issues&utm_source=github)** We accept bounties via [Bountysource](https://www.bountysource.com/?utm_campaign=plugin&utm_content=tracker%2F40949&utm_medium=issues&utm_source=github).