add captureable tech for Dune 2000
InfDeath -> DeathType renaming.
UpgradeRules for InfDeath -> DeathType renaming.
Merge pull request #5891 from Mailaender/d2k-captureable-tech

Added captureable tech for Dune 2000
Merge pull request #6372 from reaperrr/infdeath-to-deathtype

Renamed InfDeath to DeathType
Fixes #6068 & #4605