README doesn't have installation and/or getting started instructions

[SgtPooki]

Is your feature request related to a problem? Please describe. I am starting a new project using aegir and noticed that there is no "getting started" or "installation" instructions.

Describe the solution you'd like Provide a small snippet of instructions that inform users how to kick off a new project using aegir.

Describe alternatives you've considered I figure I'm supposed to:

npm install -D aegir
mkdir -p src test ...

but...

1. what is next?
2. Is Item 1 above different for a typescript/esm/cjs/etc.. repo?
3. What about for an existing repo?
4. What tools does aegir replace?

Additional context N/A

[SgtPooki]

@hugomrdias @achingbrain would you two be open to me throwing a PR together to add a getting started section to the README?

[achingbrain]

Please do, or if you want to create a 'bootstrap' command or standalone create-aegir-app tool or something that spits some default files out?

[SgtPooki]

ok sounds good. will keep this on my list