Add a button to save/share my REPL

[amoutonbrady]

Context

At the moment 100% of the shared playground are store in a Cloudflare KV store.
That means that every REPL that's being shared are anonymous.
The issue is that people can't get a list of all of their REPL.
Implementing the Solid account strategy would allow us and our users to bypass this limitation.

User Stories

• As an authenticated user, when I'm done with my REPL, I can click on the save button which saves the REPL and copy the URL of this REPL in my clipboard.

Functional rules

Given	When	Then
I'm on the playground	I click on the "Save" button	I get a success message indicating me that my playground has been saved and that the URL has been copied to my clipboard

Technical details

We'll need to detect whether the REPL is a new one or an existing one.

• We can save a new REPL of a user via the following endpoint: https://github.com/solidjs/solid-service-api#create-post-repl
• We can update a REPL of a user via the following endpoint: https://github.com/solidjs/solid-service-api#update-put-replid
• The API repository with the documentation that comes with it is located here: https://github.com/solidjs/solid-service-api
• The API is hosted here: https://api.solidjs.com