WIP Build commands table

[GuillaumeMMM]

Related Issue: #73

The goal of this PR is to give the data-navigator users a way to easily generate a table of navigation commands.

Steps:

• Create a custom table element
• Add api to rendering module
• Manual tests with both api & handmade declarative custom element
• Make sure it works with docs examples, & intergate with docs
• Test with screen readers / browsers
• Explore better commands table generation based on dimensions ?

Tested on:

• Voiceover + Safari / Chrome
• NVDA + Edge / Firefox

[domoritz]

Marking as draft for now. When it's ready for a review, you can mark it as ready.