Merge Use Index map in PGM

This PR enables using an index map to create the coarse level using PGM for distributed matrices. IMO this simplifies the PGM implementation, since there is no 'manual' implementation needed anymore.
This also has some consequences for the `distributed::Matrix` class. Namely, when creating a matrix with from local and non-local parts, an index map should be supplied, instead of the list of vectors. Again, I think this should simplify the interface. Note that currently there is no getter for the index map, since it's not necessary. But it might be useful for consistency.

Related PR: #1639

Author: MarcelKoch

benchmark/test/reference/distributed_solver.profile.stderr

@@ -36,6 +36,10 @@ DEBUG: begin components::fill_array
 DEBUG: end   components::fill_array
 DEBUG: begin components::fill_array
 DEBUG: end   components::fill_array
+DEBUG: begin components::fill_array
+DEBUG: end   components::fill_array
+DEBUG: begin components::fill_array
+DEBUG: end   components::fill_array
 DEBUG: begin copy(<typename>)
 DEBUG: begin copy
 DEBUG: end   copy
@@ -92,8 +96,6 @@ DEBUG: begin copy
 DEBUG: end   copy
 DEBUG: begin copy
 DEBUG: end   copy
-DEBUG: begin copy
-DEBUG: end   copy
 DEBUG: begin components::convert_idxs_to_ptrs
 DEBUG: end   components::convert_idxs_to_ptrs
 DEBUG: begin components::convert_idxs_to_ptrs

benchmark/test/reference/spmv_distributed.profile.stderr

@@ -52,6 +52,10 @@ DEBUG: begin components::fill_array
 DEBUG: end   components::fill_array
 DEBUG: begin components::fill_array
 DEBUG: end   components::fill_array
+DEBUG: begin components::fill_array
+DEBUG: end   components::fill_array
+DEBUG: begin components::fill_array
+DEBUG: end   components::fill_array
 DEBUG: begin copy(<typename>)
 DEBUG: begin copy
 DEBUG: end   copy
@@ -108,8 +112,6 @@ DEBUG: begin copy
 DEBUG: end   copy
 DEBUG: begin copy
 DEBUG: end   copy
-DEBUG: begin copy
-DEBUG: end   copy
 DEBUG: begin components::convert_idxs_to_ptrs
 DEBUG: end   components::convert_idxs_to_ptrs
 DEBUG: begin components::convert_idxs_to_ptrs

benchmark/test/reference/spmv_distributed.profile.stdout

@@ -5,7 +5,7 @@
         "comm_pattern": "stencil",
         "spmv": {
             "csr-csr": {
-                "storage": 10948,
+                "storage": 11476,
                 "time": 1.0,
                 "repetitions": 1,
                 "completed": true

benchmark/test/reference/spmv_distributed.simple.stdout

@@ -5,7 +5,7 @@
         "comm_pattern": "stencil",
         "spmv": {
             "csr-csr": {
-                "storage": 10948,
+                "storage": 11476,
                 "max_relative_norm2": 1.0,
                 "time": 1.0,
                 "repetitions": 10,

benchmark/test/reference/spmv_distributed_dcomplex.simple.stdout

@@ -5,7 +5,7 @@
         "comm_pattern": "stencil",
         "spmv": {
             "csr-csr": {
-                "storage": 16772,
+                "storage": 17300,
                 "max_relative_norm2": 1.0,
                 "time": 1.0,
                 "repetitions": 10,