use some existing build tool to build the packages

[bcdarwin]

Currently everything in the container is built 'by hand', i.e. via manual git clone/wget/curl; make; etc., which doesn't make much sense:

• no build caching (this is also a huge waste of developer time in the event of build failure)
• good compiler flags aren't automatically set
• limited testing (have to enable manually)

It seems like a general solution is to use an existing package manager to build all the packages. Some candidates: Spack (already in use at MICe), EasyBuild, Nix/Guix (lack many needed packages so they'd still need to be installed on top) or distribution package managers (e.g. NeuroDebian, Gentoo Science overlay). We could also consider starting from a NeuroDocker container (although there are some issues e.g. ants needs to be configured to build with MINC, the MINC toolkit version needs updating upstream, etc.)