Allow schema files to be edited in the browser

[lane711]

In the future of SonicJs we will want to allow developers evaluating SonicJs or nontechnical users (like web designers) to run an instance of SonicJs in our Cloudflare account.

There will be a generous free tier always, with low pricing in general

In order for this to happen we need to allow the user to manage their schema from the back end admin section. I

Initially this will just be editing schema configuration in a text area.

later we can add a more intuitive UI