Add BLT package (#19410)
Add BLT package (#19410)

* Add BLT package

* Switch install function

Co-authored-by: Adam J. Stewart <023e75a89b1f5ca1e59909f8756c185885836ad9@gmail.com>

* Add type='run' to cmake dependency

Co-authored-by: Adam J. Stewart <023e75a89b1f5ca1e59909f8756c185885836ad9@gmail.com>

* Add git attribute to BLT

Co-authored-by: Adam J. Stewart <023e75a89b1f5ca1e59909f8756c185885836ad9@gmail.com>
LLNL/spack,LLNL/spack,iulian787/spack,LLNL/spack,iulian787/spack,LLNL/spack,iulian787/spack,iulian787/spack,LLNL/spack,iulian787/spack