Package api v2.2 migration

[duperray]

• the 2 repos meshing and meshing_supersede where migrated using the spack repo migrate ... command.
• the directories layout follow the spack recommendation
• namespaces for lihpc repos where defined as lihpc.meshing and lihpc.meshing_supersede.
• machine-types mock package was not deleted, but probably should when @obressand-cea will release it on github.
• the migrating process forgot about a few depends_on("c") and missed spack -> spack.package imports (fixed in a separated commit).
• Dockerfile and shell script use now spack v1.1.1 but should be tested. (recipe repo artificially point on this branch)
• it seems the eigen deps is fixed on 3.3 by cmake which is not the case in the recipes
• qwtcharts need a qwt_compat.h only available until qwt-6.1, this constraint should probably be expressed in it's recipe.

Lastly, this MR should only be merged when production is ready to use spack-v1