Previously type of emulated UE was static parameter of particular software
release - it was possible to simulate UE and attach to cells only of the RAT of
particular template.

In MultiRU it will be possible to generally emulate all kind of UEs - both LTE
and NR all at the same time, and attach them to LTE and NR cells
simultaneously.

-> Switch type of UE to be runtime parameter as a preparatory step for that.

URLs of software releases changes (we remove lte and nr in names), but here we
do not care about backward compatibility because currently there are just a few
UEsim deployments and migration should be easy.