[C++] Review hardcoded "lib" paths in Find$PACKAGE.cmake related to endogenous libraries

[asfimport]

See #4024 (comment). We should try to use a more portable pattern for finding these libraries (in the event that libraries are installed in lib64, for example)

Reporter: Wes McKinney / @wesm

_{Note: This issue was originally created as ARROW-5021. Please see the migration documentation for further details.}