Define `~/.containenv/containenvrc` format about containment HOT 3 OPEN

Current thought is:

[<installer>]
<package>
<package>
<package>

[<installer>, <installer>]
<package>

[apt-get, yum, apk]
vim
git

[pip]
pytest
ipython

from containment.

Logic could be something like:

image_installers = from_image.installers  # "ubuntu"
for section in ini_sections:
    for installer in section.installers:
        if installer in image_installers:
            for package in section.packages:
                installer.install(package)

from containment.

OK so the newly consensed on design is:

[technology]
    metadep1
    metadep2

containenv shall prefer the tech specific installer and use the OS installer secondarily.
containenv shall use a custom map to determine whether a tech specific installer exists.

from containment.