FindLAPACK Add support to pkg-config

Is it possible to add the support to pkg-config to get similar feature as in FindBLAS with BLA_PREFER_PKGCONFIG please ?

Cc: @DerDakon

For reference, FindBLAS learned to use pkg-config in !1599 (merged).

added triage:mr-welcome label

mentioned in merge request !5696 (merged)

closed with merge request !5696 (merged)

closed with commit d21ad02d