Report found versions of required perl modules

Report found versions of required perl modules

Configure tests for the presence of perl modules required for TAP tests,
and that they meet specified minimum version requirements. This patch
makes it report the version of the module that's actually found rather
than just an 'ok' message. This will help in deciding if we can upgrade
minimum requirements for these modules.

Discussion: https://postgr.es/m/f5e1d308-4e33-37a7-bdf1-f6e0c75119de@dunslane.net