[devfix] Simplify PostgreSQL install

[mcovalt]

This PR simplifies the PostgreSQL install by using the "binary" package in requirements.txt. It allows a much simpler developer environment setup. All the dependency steps in the Wiki can be removed if this is merged.

Background

In version 2.7, the PostgreSQL driver pyscopg2 delivered the pre-compiled binary along with the source. This allowed developers to install the driver without the need to compile it with external dependencies. It also allowed a production environment to compile it from source with the the --no-binary flag in pip. This is standard practice for PyPI packages.

This was changed in version 2.8, however. There are now two interchangeable packages:

• pyscopg2-binary: always installs the pre-compiled driver (recommended for development environments)
• psycopg2: always builds the driver from source (recommended for production environments)

Fix

The psycopg2 requirement was replaced with psycopg2-binary. During the Docker build stage, the psycopg2 requirement is swapped back in.

[debboutr]

this works as prescribed, tried out both the dockerfile and the new env. The only thing that I'm not sure of is whether or not we can take out the Visual Studio install that we have in the wiki. I can install it on my windows machine, but I need admin rights to uninstall. I updated the developer setup on the wiki to account for this. Thanks!