Feat: serialize Pluto.activate_notebook_environment to allow running Pluto notebooks as scripts

[pankgeorg]

Towards: #2572 (comment)

[github-actions]

Try this Pull Request!

Open Julia and type:

julia> import Pkg
julia> Pkg.activate(temp=true)
julia> Pkg.add(url="https://github.com/fonsp/Pluto.jl", rev="pg/serialize-pkg")
julia> using Pluto

[disberd]

Wouldn't this break packages that use notebooks as included files (unless they explicitly avoid using PlutoPkg).
I didn't try the PR but it would seem from the code that when included outside of Pluto this would create, activate and instantiate the notebook environment instead of the one of the including package

[pankgeorg]

Yes that is a good point. We probably want something more sophisticated here.