debuggable installations in eic/containers: wire --debug-source and --debug-symbols into the dbg environment

[SebastianPaucar]

This PR adds the framework related to the following design discussion for debuggable installations in spack packages:

• PR 52768 (spack/spack): DWARF-referenced source hook and symbol splitting plus GDB init for debuggable installations.
• PR 19 (spack/compiler-wrapper): -ffile-prefix-map=<staging>=. and --build-id injection in compiler-wrapper.
• PR 5353 (spack/spack-packages): set SPACK_DEBUG_PREFIX_MAP for -ffile-prefix-map=<stage>=. injection at compiler-wrapper level.
• Spack Debuggable Installations Demo
  (SebastianPaucar/spack): --debug-source and --debug-symbols PoC container demo (verified end-to-end).

In summary, this PR adds --debug-source and --debug-symbols to spack install when ENV=dbg, via a new conditional in scripts/build-eic.sh that appends to SPACK_INSTALL_FLAGS.

Worth noting: SPACK_INSTALL_FLAGS is also read by the runtime --use-buildcache only install stages, so these flags will currently reach install-from-buildcache too, not just fresh builds.

[wdconinc]

@SebastianPaucar In master (#393) we added a mirror for the source that has the ssl certificate errors in CI here.

[SebastianPaucar]

@SebastianPaucar In master (#393) we added a mirror for the source that has the ssl certificate errors in CI here.

Branch updated with #393. Also implemented OCI push/autopush (per mirrors.yaml.in) and fetch of debug info (sources and symbols) into/from GHCR and eicweb mirrors (verified locally with my GHCR), according to this commit in my Spack branch feature/debuggable-installations-v1.2.2 #a5874e8. Working in the documentation.

[SebastianPaucar]

@SebastianPaucar In master (#393) we added a mirror for the source that has the ssl certificate errors in CI here.

Noticed some of the newer cherry-picks in spack-packages.sh were missing. Added.

[wdconinc]

It seems this PR has created a whole new spack build cache at https://eicweb.phy.anl.gov/containers/eic_container/container_registry/154 because we reuse the branch name as container registry name ;-)