feat: add persistent app layouts to template

[mcavaliere]

trafficstars

Fix #242

Changes

Sets _app.tsx up to render a getLayout function for any page (or component) if it exists. This allows faster navigation between pages, since layouts that are the same between pages will not be re-rendered (since their element subtrees are the same).

References:

• Basic Features: Layouts | Next.js
• Persistent Layout Patterns in Next.js – Adam Wathan
• Next.js Page Layouts and Dynamic Content | Cut Into The Jamstack

Also includes:

• References shared footer component in logged in / logged out layouts
• Makes nav links consistently use next/link around the Chakra Link component
• Adds 3 placeholder pages for the default nav links

Screenshots

(prefer animated gif)

Checklist

• [ ] Requires dependency update?
• [ ] Generating a new app works

Fixes #xxx

[mthomps4]

We should revisit this PR with the new Layout features dropping

[mthomps4]

Almost a year old -- closing

[mcavaliere]

😢

[mthomps4]

😢

Can re-open with new Next stuff