Genex: add $<TARGET_FILE_PREFIX:...> and $<TARGET_FILE_SUFFIX:...>
Provides the following generator expressions:
- $<TARGET_FILE_PREFIX:tgt>
- $<TARGET_LINKER_FILE_PREFIX:tgt>
- $<TARGET_FILE_SUFFIX:tgt>
- $<TARGET_LINKER_FILE_SUFFIX:tgt>
These capabilities complement MR !3190 (merged) and is also needed to solve issue #18771 (closed).