Feature/bcss 21582 investigation datasets UI app (#141)

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## Description

<!-- Describe your changes in detail. -->
Creating a new UI application to easily create the dictionaries
necessary for the investigation datasets util.

## Context

<!-- Why is this change required? What problem does it solve? -->
Makes the testing on the investigation dataset much easier by giving
testers the option to select values from dropdowns to populate
dictionaries that will be used in the investigation dataset utility.
Also provides them with the necessary imports

## Type of changes

<!-- What types of changes does your code introduce? Put an `x` in all
the boxes that apply. -->

- [x] Refactoring (non-breaking change)
- [x] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would change existing
functionality)
- [ ] Bug fix (non-breaking change which fixes an issue)

## Checklist

<!-- Go over all the following points, and put an `x` in all the boxes
that apply. -->

- [x] I am familiar with the [contributing
guidelines](https://github.com/nhs-england-tools/playwright-python-blueprint/blob/main/CONTRIBUTING.md)
- [x] I have followed the code style of the project
- [ ] I have added tests to cover my changes (where appropriate)
- [x] I have updated the documentation accordingly
- [ ] This PR is a result of pair or mob programming

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Author: adrianoaru-nhs