Emailer - update name request(before expiry, expiry, renewal, upgrade) processor to work with alternate name changes

Update email processor(s) such that we are able to work with alternate_name entries where required. With the new data model, SPs will need to use alternate_name similar to the way we use a legal_entity record.

**TODOs**
Do following for email processor(s) relevant to this ticket:
- [ ] Do work in legal name branch
- [ ] Update to work with alternate names and legal entities
- [ ] Update versioning logic where required. May be still using versioning approach used in old data model
- [ ] There may be some other misc updates required to get processor working. Update as appropriate.
- [ ] Update worker.py as required
- [ ] Update tests relevant to this email processor

Locate the relevant email processor, worker.py, and its existing tests, then read how legal_entity and alternate_name are represented in the new data model. Update the processor and versioning behavior for the listed workflows, and consider the work done when the relevant tests cover alternate names, legal entities, and the required email processing paths.

Written by the indexing model from the issue text.