Add QE 6.8 pw2qmcpack patch.

[ye-luo]

Proposed changes

QE 6.8 with pw2qmcpack. CMake has become the preferred way for building QE.

What type(s) of changes does this code introduce?

• New feature

Does this introduce a breaking change?

• No

What systems has this change been tested on?

epyc-server

Checklist

• Yes. This PR is up to date with current the current state of 'develop'

[jtkrogel]

Just an aside: what does QE still need to be able to accept pw2qmcpack into their repo?

[ye-luo]

If I'm a reviewer,

1. I would like to see clib/esh5_interfaces.c our hdf5 abstraction going away. It is half of the lines and it is not using iso_c_binding. So it is already a potential source of problems. We need to use the same hdf5 abstraction as QE.
2. Not using hdf5 hl library. It has poor performance and we can use features from 1.10 instead.
3. Drop 1.6 API, which may need QMCPACK side change as well.

[prckent]

Release notes https://github.com/QEF/q-e/releases/tag/qe-6.8

[prckent]

Looking at this now.

[prckent]

Works for me. I was able to build QE after cmake configuration and get a pw2qmcpack executable included along with the standard binaries. I'll update our nightly tests scripts once merged.

Thanks for doing this so quickly after the QE6.8 release.

[prckent]

Start testing in-house