Add FCCconfig tests to k4geo

[atolosadelgado]

Hi,

Would it be worth integrating downstream CI tests into k4geo to prevent issues like this [1]? I'm specifically thinking about FCCconfig (and maybe CLDconfig), which manage the configuration for running the full chain.

After a quick chat with @jmcarcell, it seems the fastest and simplest solution would be to add tests in k4geo equivalent to those in FCCconfig.

@BrieucF @andresailer, what do you think?

[1] #438