Allow again CMake to look for Apache Arrow at configuration time by default.
Allow again CMake to look for Apache Arrow at configuration time by default.

Revert "Revert "Look for Apache Arrow by default at configuration time""
This reverts commit aef20f136f18546c89985b04fdd31eacb437665d now that all conflicts
have been fixed.

karies/root,karies/root,root-mirror/root,root-mirror/root,root-mirror/root,olifre/root,olifre/root,olifre/root,karies/root,olifre/root,karies/root,olifre/root,olifre/root,root-mirror/root,karies/root,root-mirror/root,karies/root,root-mirror/root,karies/root,karies/root,karies/root,olifre/root,root-mirror/root,olifre/root,olifre/root,olifre/root,root-mirror/root,root-mirror/root,karies/root,root-mirror/root,olifre/root,karies/root,root-mirror/root