elegant: update rel.stages, use YAML variants file

MPI/elegant/files/variants.merlin6

@@ -1 +0,0 @@
-elegant/2020.2.0_merlin6	stable		gcc/8.4.0 openmpi/3.1.6_slurm gsl/2.6

MPI/elegant/files/variants.rhel6

@@ -1,5 +0,0 @@
-elegant/2020.2.0	stable		gcc/8.4.0 openmpi/3.1.6 gsl/2.6
-elegant/32.0.0		deprecated	gcc/5.4.0 openmpi/1.10.4
-elegant/33.1.2		deprecated	gcc/5.4.0 openmpi/1.10.4
-elegant/34.2.0		deprecated	gcc/7.3.0 mpich/3.2.1
-

MPI/elegant/files/variants.yaml

@@ -0,0 +1,41 @@
+overlay: base
+relstage: stable
+
+elegant/32.0.0:
+  - with: gcc/5.4.0 openmpi/1.10.4 
+    systems: rhel6
+    relstage: deprecated
+
+elegant/33.1.2:
+  - with: gcc/5.4.0 openmpi/1.10.4
+    systems: rhel6
+    relstage: deprecated
+
+elegant/34.2.0:
+  - with: gcc/7.3.0 mpich/3.2.1
+    systems: rhel6
+    relstage: deprecated
+
+elegant/2020.2.0:
+  - with: gcc/8.4.0 openmpi/3.1.6
+    systems: rhel6
+         
+elegant/2020.2.0_merlin6:
+  - with: gcc/8.4.0 openmpi/3.1.6_slurm
+    systems: slurm
+
+elegant/2021.4.0:
+  - with: gcc/10.3.0 openmpi/4.0.5
+    systems: rhel6
+elegant/2021.4.0_slurm:
+  - with: gcc/10.3.0 openmpi/4.0.5-1_slurm
+    relstage: deprecated
+    systems: slurm
+elegant/2021.4.0-1_slurm:
+  - with: gcc/10.3.0 openmpi/4.0.5-1_slurm
+    relstage: deprecated
+    systems: slurm
+elegant/2021.4.0-2_slurm:
+  - with: gcc/10.3.0 openmpi/4.0.5-1_slurm
+    systems: slurm
+