Add vim text editor to the container

[rahmans1]

Add a light weight text editor to the container. Just chose vim because that's what I am used to.

Resolves #59

[buddhasystem]

Ouch! vim! :)
Do we already have nano, at least?

[plexoos]

An editor can be installed... But I don't think that is customary to do so. Look at the various images distributed by major companies, they don't include editors or any additional tools beyond the main application . I guess when people use containers they usually assume a different workflow (although you can install whatever you want when you run it as root).

In our case when we run esi-shell the $HOME dir is mounted inside the container by default. Can we use editors installed on the host to modify files in the user HOME, so the changes are also visible within the container?

[plexoos]

Anyway, that said, it makes a bit more sense to install external tools with the system package manager rather than spack.
I would like to reserve the spack environment for only direct dependencies to our primary applications.
See next commit