Generic svelte component for json objects

[mrbrianevans]

Add component for arbitrary simple key-value pair objects.

Eg input:

{
    "name": "user1",
    "account_created_on": "2020-10-21",
    "public": true
}

• Make sure dates, numbers and booleans are parsed correctly
• Rename keys to sentence case if they are camelCase or snake_case etc

[mrbrianevans]

A start to this was made in #27 (specifically 2edfd6d) with a component to display instagram profiles being generic.

There are various improvements needed:

• it should be the same component for deeply nested and shallow objects
• use section headings if there is a lot of data under a key (go from h1-h6)
• sort by most shallow at the top, deeply nested last on the page
• styling for the outer component that any child <a> or <h1> are styled correctly

[mrbrianevans]

Can use <svelte:self /> special component to render recursively. This should remove the need for Preact.