Unexpected consequence of #7365 - previously `OPENCASCADE_LIBRARIES` supposed to be a list of libraries filepaths, but after refactor `OpenCASCADE_LIBRARIES` end up being both list of library names and list of filepaths.
And since link directories for the names was not provided, it failed to find the libraries to link.
If using OpenCASCADEconfig it wouldn't fail as cmake would evaluate library names as imported target names.
To fix it and simplify it even further, in case of manually provided paths, it now creates `OpenCASCADE_INTERFACE` target and stores it in `OpenCASCADE_LIBRARIES` - target will automatically have all the includes, library names and library dirs.
Andrej730