feat: remove resource_group (concurrency limiting)

Now that we build with unique tags, there shouldn't be any cross talk anymore.

containers/jug/dev.Dockerfile

@@ -54,7 +54,7 @@ RUN declare -A target=(                                                 \
  && spack config blame packages                                         \
  && spack config --scope user add "config:suppress_gpg_warnings:true"   \
  && spack config --scope user add "config:build_jobs:${jobs}"           \
- && spack config --scope user add "config:db_lock_timeout:${jobs}0"     \
+ && spack config --scope user add "config:db_lock_timeout:${jobs}00"    \
  && spack config --scope user add "config:source_cache:/var/cache/spack" \
  && spack config --scope user add "config:install_tree:root:/opt/software" \
  && spack config --scope user add "config:ccache:true"                  \