[Feature Request]: Additional fields on customer/unit registration

### Preflight Checklist

- [x] I have read the [Contributing Guidelines](https://github.com/EnAccess/micropowermanager/blob/main/CONTRIBUTING.md) for this project, if it exists.
- [x] I agree to follow the [Code of Conduct](https://github.com/EnAccess/micropowermanager/blob/main/CODE_OF_CONDUCT.md) that this project adheres to.
- [x] I have searched the [issue tracker](https://github.com/EnAccess/micropowermanager/issues) for a feature request that matches the one I want to file, without success.

### Problem Description

When submitting our lists to the facilities we participate, they request additional information that MPM doesn't have currently. These fields would also be helpful on a daily basis to organize customer information.

### Proposed Solution

Adding the following fields:

- Locality
- District
- Administrative Post
- Province
- Customer ID Number

These can also be dropdown lists (with the exception of Customer ID number). I can share a file with this information where the user would just have to select the correct province, District, locality, and administrative post.

### Alternatives Considered

Currently, we include this information on the field "Street" which isn't ideal and came make things difficult when submitting lists.

### Additional Information

[Administrative Posts_14072026.xlsx](https://github.com/user-attachments/files/30052156/Administrative.Posts_14072026.xlsx)

Start by tracing the existing customer and unit registration entry points, including how submitted fields are stored and displayed. Review the attached Administrative Posts_14072026.xlsx for the proposed location data; done means the five fields are available where registration is handled, with selectable administrative values and a customer ID number.

Written by the indexing model from the issue text.