FindSQLite3: Use pkg-config for SQLite3 hints
This adds pkg-config hints to the FindSQLite3 module in cases where SQLite3 library is not installed in the usual locations, but pkgconf/pkg-config might still find it.
This adds pkg-config hints to the FindSQLite3 module in cases where SQLite3 library is not installed in the usual locations, but pkgconf/pkg-config might still find it.