Mesh: Remove unnecessary edge draw flag

As described in #95966, replace the `ME_EDGEDRAW` flag with a bit
vector in mesh runtime data. Currently the the flag is only ever set
to false for the "optimal display" feature of the subdivision surface
modifier. When creating an "original" mesh in the main data-base,
the flag is always supposed to be true.

The bit vector is now created by the modifier only as necessary, and
is cleared for topology-changing operations. This fixes incorrect
interpolation of the flag as noted in #104376. Generally it isn't
possible to interpolate it through topology-changing operations.

After this, only the seam status needs to be removed from edges before
we can replace them with the generic `int2` type (or something similar)
and reduce memory usage by 1/3.

Related:
- 10131a6f62
- 145839aa42

In the future `BM_ELEM_DRAW` could be removed as well. Currently it is
used and aliased by other defines in some non-obvious ways though.

Pull Request #104417

source/blender/blenloader/intern/versioning_legacy.c

@@ -1467,7 +1467,7 @@ void blo_do_versions_pre250(FileData *fd, Library *lib, Main *bmain)
 
     for (me = bmain->meshes.first; me; me = me->id.next) {
       if (!me->medge) {
-        BKE_mesh_calc_edges_legacy(me, true); /* true = use #MFace.edcode. */
+        BKE_mesh_calc_edges_legacy(me); 
       }
       else {
         BKE_mesh_strip_loose_faces(me);