ugtrain: introduce 'or' checks

We need to check a value with multiple checks linked by 'or'. This
is especially useful to reduce the number of configured values and
type checks. So introduce 'or' checks.

Example: Droid, Cyborg and VTOL factories in Warzone 2100 use the
same functionality (factory) data structure.
examples: warzone2100: 32-bit: cheat Cyborg and VTOL factories

We use the new 'or' checks to make this possible without
duplicating value entries in the config.