Define behavior when conflicting idspaces are specified

There are different potential sources of conflict or ambiguity:

1. Contraction
- 1. when an alternate prefix is specified for a `builtin` idspace
- 2. when alternate prefixes are specified for domain idpsaces
2. Expansion
- 1. When a `builtin` idspace is overridden
- 2. When alternate expansions are provided for domain idspaces

_Originally posted by @hrshdhgd in https://github.com/INCATools/ontology-access-kit/issues/702#issuecomment-1981166963_

Review the originating discussion in issue 702, especially the referenced comment, and map the four contraction and expansion conflict cases listed here. Define the intended behavior for each case and document the resulting decision so the issue has an unambiguous completion criterion.

Written by the indexing model from the issue text.