Build issues with Houdini and cmake

[cpichard]

Describe the bug

Here is a summary of the issues preventing successful building with cmake and houdini:

1. Houdini 21.0: The build fails due to missing shared_lib_targets (usdSkelImaging/hboost_python) in HoudiniConfig.cmake.
2. Houdini 20.5: The build fails with the error cannot find -lhdsi. This appears to be related to the changes introduced in this commit.
3. Houdini 20.0: The build also fails with cannot find -lhdsi, stemming from the same commit mentioned above.

[autodesk-oss-arnold-bot]

Issue synced internally to ARNOLD-17025

[autodesk-oss-arnold-bot]

Issue synced internally to ARNOLD-17387