Docs: Improve the README for first onlookers of the openlab-cli

[cdharris]

@blahah & @NiklasTR does this direction look good to continue? is it roughly at the level of detail and complexity as you'd expect as an initial introduction to the openlab tool?

Mostly focused for now on helping curious providers, researchers, and other savvy interested biocomputational adjacent folks in the right direction.

It's missing a focus on developer onboarding for now, but this languaging depends on the contribution strategy overall that is currently being worked out (platforms / programmes, core team, contributors, etc) - we'll get to that soon.

Any feedback before I proceed with another round of edits and additions?