chore(io): remove Code_Aster reader module stub

Remove the HDF5-backed `AsterReader` wrapper from the default package tree so
the slim IO surface only exposes the maintained mesh ingest path.

- Drop `src/io/AsterReader.jl` (mesh/results includes are no longer shipped here).

src/io/AsterReader.jl

@@ -1,25 +0,0 @@
-# This file is a part of JuliaFEM.
-# License is MIT: see https://github.com/JuliaFEM/AsterReader.jl/blob/master/LICENSE
-
-module AsterReader
-
-using HDF5
-
-"""
-    parse_node_id(node_name)
-
-Return id number from node name. Usually the node name contains the id number,
-i.e. N123 => 123 and so on.
-
-"""
-function parse_node_id(node_name)
-    m = match(r"\d+", node_name)
-    m != nothing || error("Unable to parse id from node name $node_name.")
-    return tryparse(Int, m.match)
-end
-
-include("read_aster_mesh.jl")
-include("read_aster_results.jl")
-export aster_read_mesh
-
-end