ER: [docs] Initial data page problems

### Emergent Requirement - The create initial data page docs is confusing to someone new to it

- `app/core/intial_data/*.json` files are present for older initial data but not generated for the current one.
- This was an extra step that was optimized out.
- We might still needed the `json` file. It serves the purpose of keeping track of what our actual initial data are vs. what's in the spreadsheet. If later on we import from the spreadsheet again and the `json` file changes, we'll know the source data changed.
- [need decision] Should we keep using the `json` files or are the actual migration files enough? The problem is the migration files still have a manual step to introduce differences.
- need language saying not to keep the downloaded `.csv` file and `app/core/scripts/*.py` genenerated file
- `manage.py dbshell` instruction doesn't work anymore to get into a database shell
- either update docs to use `./scripts/db.sh`
- or install `postgres` in the Docker image
- [need decsion] do we need `manage.py dbshell` at this point?
- probably `manage.py shell_plus`. Check to see if that works first

### Issue you discovered this emergent requirement in

- #35

### Date discovered 2024-10-28

### Did you have to do something temporarily

- [x] YES
- manual explanation of the instructions and don't commit the intermediate files
- [ ] NO

### Who was involved

@del9ra
@fyliu

### What happens if this is not addressed

Someone new to the project could be confused about what to do.

### Resources

- [Create initial data migrations page](https://hackforla.github.io/peopledepot/contributing/howto/create-initial-data-migrations/)

### Recommended Action Items

- [ ] Make a new issue
- [ ] Discuss with team
- [ ] Let a Team Lead know

### Potential solutions \[draft\]