Reimplement (named) constituent jobs (+globbing) based on nix-eval-jobs

Depends on https://github.com/nix-community/nix-eval-jobs/pull/349 & #1421.

Almost equivalent to #1425, but with a small change: when having e.g. an
aggregate job with a glob that matches nothing, the jobset evaluation is
failed now. This was the intended behavior before (hydra-eval-jobset
fails hard if an aggregate is broken), the code-path was never reached
however since the aggregate was never marked as broken in this case
before.

t/jobs/constituents-no-matches.nix

@@ -0,0 +1,20 @@
+with import ./config.nix;
+{
+  non_match_aggregate = mkDerivation {
+    name = "mixed_aggregate";
+    _hydraAggregate = true;
+    _hydraGlobConstituents = true;
+    constituents = [
+      "tests.*"
+    ];
+    builder = ./empty-dir-builder.sh;
+  };
+
+  # Without a second job no jobset is attempted to be created
+  # (the only job would be broken)
+  # and thus the constituent validation is never reached.
+  dummy = mkDerivation {
+    name = "dummy";
+    builder = ./empty-dir-builder.sh;
+  };
+}