readAntares thermal cluster availability is broken

[pl-buiquang]

The .importThermal (importOutput.R) does not work with the API.
Contrary to the non-api code which list the ts-numbers for thermal (l. 544) which filters unexisting files, the api (l570) returns the whole list of clusters (even if the ts-number file is not present).
When reading the ts-numbers for these unactive thermal clusters, it returns a null tsId list which cause probleme latter on.
We should filter the nameCls and tsIds, removing those empty clusters (before l584).