Added illustration to explain relationship between a REPL, REBL, and your editor\client

[jaidetree]

Problem

After setting up a couple example repos I've seen confusion around the relationship between the REPL, REBL, and an editor\repl client.

Solution

• Show that you connect to the REBL CLI REPL. You don't directly connect your editor to the REBL tool itself.
• Created a stylized illustration to show the relationship between a cli REPL, REBL, and an editor.
• Used entirely open source fonts and icons from the DejaVu Sans Mono Nerd Font
• Added supported copy accompanying illustration

(proportions are smaller in this PR container than the README.md)

Changes can be previewed at https://github.com/cognitect-labs/REBL-distro/blob/f0eb07c437a3c502b5ce1716742698d759fadefd/README.md

Notes

• If any changes are required I am happy to make them upon request.
• I can provide the .ai illustrator source file as well in addition to SVG or PDF formats.

[jaidetree]

Old image for reference