Clarify who adds the CDI ELResolver

Currently both CDI impls add their ELResolver to Faces (either via Code like Weld or faces-config like OWB)

and we in Faces add them manually, too

IMO CDI should remove their logic, we should integrate CDI, not vice versa

Compare how Weld and OWB register their ELResolver with Faces, including Weld's code path and OWB's faces-config path, against Faces' own manual registration. Confirm which project should own the registration and document the expected single integration path as done.

Written by the indexing model from the issue text.