tbd: allow json with comments and trailing commas

[vincentullmann]

Changelog Description

allow comments and trailing commas in environment configs

Additional review information

code wise this is mostly just this (for now)

try:
    import json5 as json
except ImportError:
    import json

but there are probably a few more places that might need minor adjustments.

I'm just putting this PR out here as a wip / idea up for discussion