Push app env var related code into the env builder

[georgethebeatle]

Blockers

#3165 : This PR introduces a MEMORY LIMIT env var that can also be pushed into the env builder

Background

In the CFProcess controller we are currently building a subset of the needed environment via an env builder and the rest is being appended at a later point. We could improve this by pushing all code that builds env vars into the env builder. The env buidler will have to take cfprocess as an additional argument.